Micro Heat Transfer Arrays, Micro Cold Plates, and Thermal Management Systems for Cooling Semiconductor Devices, and Methods for Using and Making Such Arrays, Plates, and Systems

ABSTRACT

Embodiments of the present invention are directed to heat transfer arrays, cold plates including heat transfer arrays along with inlets and outlets, and thermal management systems including cold-plates, pumps and heat exchangers. These devices and systems may be used to provide cooling of semiconductor devices and particularly such devices that produce high heat concentrations. The heat transfer arrays may include microjets, microchannels, fins, and even integrated microjets and fins.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/951,481, filed on Apr. 12, 2018, which is a continuation of U.S.patent application Ser. No. 15/283,013, filed on Sep. 30, 2016, now U.S.Pat. No. 9,953,899, which claims the benefit of the following U.S.Provisional Patent Applications:

-   -   (1) 62/355,557 filed Jun. 28, 2016 (Microfabrica Docket No.        P-US339-E-MF),    -   (2) 62/321,840 filed Apr. 13, 2016 (Docket No. P-US339-D-MF),    -   (3) 62/316,470 filed Mar. 31, 2016 (Docket No. P-US339-C-MF),    -   (4) 62/274,056 filed Dec. 31, 2015 (Docket No. P-US339-B-MF),        and    -   (5) 62/235,547 filed Sep. 30, 2015 (Docket No. P-US339-A-MF).        Each of these referenced applications is incorporated herein by        reference as if set forth in full herein.

FIELD OF THE INVENTION

The present invention relates (1) to microscale or millimeter scale heattransfer devices and systems that include active heat sink or cold platedevices having improved thermal conductance and (2) the field ofelectrochemically fabricating multi-layer micro-scale or mesoscale threedimensional structures, parts, components, or devices where each layeris formed from a plurality of deposited materials and more specificallyto use of such methods in forming microscale transfer arrays.

BACKGROUND OF THE INVENTION

Electrochemical Fabrication:

An electrochemical fabrication technique for forming three-dimensionalstructures from a plurality of adhered layers has been and is beingcommercially pursued by Microfabrica® Inc. (formerly MEMGen Corporation)of Van Nuys, Calif. under the process names EFAB™ and MICA FREEFORM®.

Various electrochemical fabrication techniques were described in U.S.Pat. No. 6,027,630, issued on Feb. 22, 2000 to Adam Cohen. Someembodiments of this electrochemical fabrication technique allow theselective deposition of a material using a mask that includes apatterned conformable material on a support structure that isindependent of the substrate onto which plating will occur. Whendesiring to perform an electrodeposition using the mask, the conformableportion of the mask is brought into contact with a substrate, but notadhered or bonded to the substrate, while in the presence of a platingsolution such that the contact of the conformable portion of the mask tothe substrate inhibits deposition at selected locations. Forconvenience, these masks might be generically called conformable contactmasks; the masking technique may be generically called a conformablecontact mask plating process. More specifically, in the terminology ofMicrofabrica Inc. such masks have come to be known as INSTANT MASKS™ andthe process known as INSTANT MASKING™ or INSTANT MASK™ plating.Selective depositions using conformable contact mask plating may be usedto form single selective deposits of material or may be used in aprocess to form multi-layer structures. The teachings of the '630 patentare hereby incorporated herein by reference as if set forth in fullherein. Since the filing of the patent application that led to the abovenoted patent, various papers about conformable contact mask plating(i.e. INSTANT MASKING) and electrochemical fabrication have beenpublished:

-   (1) A. Cohen, G. Zhang, F. Tseng, F. Mansfeld, U. Frodis and P.    Will, “EFAB: Batch production of functional, fully-dense metal parts    with micro-scale features”, Proc. 9th Solid Freeform Fabrication,    The University of Texas at Austin, p 161, August 1998.-   (2) A. Cohen, G. Zhang, F. Tseng, F. Mansfeld, U. Frodis and P.    Will, “EFAB: Rapid, Low-Cost Desktop Micromachining of High Aspect    Ratio True 3-D MEMS”, Proc. 12th IEEE Micro Electro Mechanical    Systems Workshop, IEEE, p 244, January 1999.-   (3) A. Cohen, “3-D Micromachining by Electrochemical Fabrication”,    Micromachine Devices, March 1999.-   (4) G. Zhang, A. Cohen, U. Frodis, F. Tseng, F. Mansfeld, and P.    Will, “EFAB: Rapid Desktop Manufacturing of True 3-D    Microstructures”, Proc. 2nd International Conference on Integrated    MicroNanotechnology for Space Applications, The Aerospace Co., April    1999.-   (5) F. Tseng, U. Frodis, G. Zhang, A. Cohen, F. Mansfeld, and P.    Will, “EFAB: High Aspect Ratio, Arbitrary 3-D Metal Microstructures    using a Low-Cost Automated Batch Process”, 3rd International    Workshop on High Aspect Ratio MicroStructure Technology (HARMST'99),    June 1999.-   (6) A. Cohen, U. Frodis, F. Tseng, G. Zhang, F. Mansfeld, and P.    Will, “EFAB: Low-Cost, Automated Electrochemical Batch Fabrication    of Arbitrary 3-D Microstructures”, Micromachining and    Microfabrication Process Technology, SPIE 1999 Symposium on    Micromachining and Microfabrication, September 1999.-   (7) F. Tseng, G. Zhang, U. Frodis, A. Cohen, F. Mansfeld, and P.    Will, “EFAB: High Aspect Ratio, Arbitrary 3-D Metal Microstructures    using a Low-Cost Automated Batch Process”, MEMS Symposium, ASME 1999    International Mechanical Engineering Congress and Exposition,    November, 1999.-   (8) A. Cohen, “Electrochemical Fabrication (EFAB™)”, Chapter 19 of    The MEMS Handbook, edited by Mohamed Gad-El-Hak, CRC Press, 2002.-   (9) Microfabrication—Rapid Prototyping's Killer Application”, pages    1-5 of the Rapid Prototyping Report, CAD/CAM Publishing, Inc., June    1999.

The disclosures of these nine publications are hereby incorporatedherein by reference as if set forth in full herein.

An electrochemical deposition process for forming multilayer structuresmay be carried out in a number of different ways as set forth in theabove patent and publications. In one form, this process involves theexecution of three separate operations during the formation of eachlayer of the structure that is to be formed:

-   -   1. Selectively depositing at least one material by        electrodeposition upon one or more desired regions of a        substrate. Typically this material is either a structural        material or a sacrificial material.    -   2. Then, blanket depositing at least one additional material by        electrodeposition so that the additional deposit covers both the        regions that were previously selectively deposited onto, and the        regions of the substrate that did not receive any previously        applied selective depositions. Typically this material is the        other of a structural material or a sacrificial material.    -   3. Finally, planarizing the materials deposited during the first        and second operations to produce a smoothed surface of a first        layer of desired thickness having at least one region containing        the at least one material and at least one region containing at        least the one additional material.

After formation of the first layer, one or more additional layers may beformed adjacent to an immediately preceding layer and adhered to thesmoothed surface of that preceding layer. These additional layers areformed by repeating the first through third operations one or more timeswherein the formation of each subsequent layer treats the previouslyformed layers and the initial substrate as a new and thickeningsubstrate.

Once the formation of all layers has been completed, at least a portionof at least one of the materials deposited is generally removed by anetching process to expose or release the three-dimensional structurethat was intended to be formed. The removed material is a sacrificialmaterial while the material that forms part of the desired structure isa structural material.

One method of performing the selective electrodeposition involved in thefirst operation is by conformable contact mask plating. In this type ofplating, one or more conformable contact (CC) masks are first formed.The CC masks include a support structure onto which a patternedconformable dielectric material is adhered or formed. The conformablematerial for each mask is shaped in accordance with a particularcross-section of material to be plated (the pattern of conformablematerial is complementary to the pattern of material to be deposited).In such a process at least one CC mask is used for each uniquecross-sectional pattern that is to be plated.

The support for a CC mask may be a plate-like structure formed of ametal that is to be selectively electroplated and from which material tobe plated will be dissolved. In this typical approach, the support willact as an anode in an electroplating process. In an alternativeapproach, the support may instead be a porous or otherwise perforatedmaterial through which deposition material will pass during anelectroplating operation on its way from a distal anode to a depositionsurface. In either approach, it is possible for multiple CC masks toshare a common support, i.e. the patterns of conformable dielectricmaterial for plating multiple layers of material may be located indifferent areas of a single support structure. When a single supportstructure contains multiple plating patterns, the entire structure isreferred to as the CC mask while the individual plating masks may bereferred to as “submasks”. In the present application such a distinctionwill be made only when relevant to a specific point being made.

In some implementations, a single structure, part or device may beformed during execution of the above noted steps or in otherimplementations (i.e. batch processes) multiple identical or differentstructures, parts, or devices, may be built up simultaneously.

In preparation for performing the selective deposition of the firstoperation, the conformable portion of the CC mask is placed inregistration with and pressed against a selected portion of (1) thesubstrate, (2) a previously formed layer, or (3) a previously depositedmaterial forming a portion of the given layer that is being created. Thepressing together of the CC mask and relevant substrate, layer ormaterial occurs in such a way that all openings, in the conformableportions of the CC mask contain plating solution. The conformablematerial of the CC mask that contacts the substrate, layer, or materialacts as a barrier to electrodeposition while the openings in the CC maskthat are filled with electroplating solution act as pathways fortransferring material from an anode (e.g. the CC mask support) to thenon-contacted portions of the substrate (which act as a cathode duringthe plating operation) when an appropriate potential and/or current aresupplied.

An example of a CC mask and CC mask plating are shown in FIGS. 1A-10.FIG. 1A shows a side view of a CC mask 8 consisting of a conformable ordeformable (e.g. elastomeric) insulator 10 patterned on an anode 12. Theanode has two functions. One is as a supporting material for thepatterned insulator 10 to maintain its integrity and alignment since thepattern may be topologically complex (e.g., involving isolated “islands”of insulator material). The other function is as an anode for theelectroplating operation. FIG. 1A also depicts a substrate 6, separatedfrom mask 8, onto which material will be deposited during the process offorming a layer. CC mask plating selectively deposits material 22 ontosubstrate 6 by simply pressing the insulator against the substrate thenelectrodepositing material through apertures 26 a and 26 b in theinsulator as shown in FIG. 1B. After deposition, the CC mask isseparated, preferably non-destructively, from the substrate 6 as shownin FIG. 10.

The CC mask plating process is distinct from a “through-mask” platingprocess in that in a through-mask plating process the separation of themasking material from the substrate would occur destructively.Furthermore in a through mask plating process, openings in the maskingmaterial are typically formed while the masking material is in contactwith and adhered to the substrate. As with through-mask plating, CC maskplating deposits material selectively and simultaneously over the entirelayer. The plated region may consist of one or more isolated platingregions where these isolated plating regions may belong to a singlestructure that is being formed or may belong to multiple structures thatare being formed simultaneously. In CC mask plating as individual masksare not intentionally destroyed in the removal process, they may beusable in multiple plating operations.

Another example of a CC mask and CC mask plating is shown in FIGS.1D-1G. FIG. 1D shows an anode 12′ separated from a mask 8′ that includesa patterned conformable material 10′ and a support structure 20. FIG. 1Dalso depicts substrate 6 separated from the mask 8′. FIG. 1E illustratesthe mask 8′ being brought into contact with the substrate 6. FIG. 1Fillustrates the deposit 22′ that results from conducting a current fromthe anode 12′ to the substrate 6. FIG. 1G illustrates the deposit 22′ onsubstrate 6 after separation from mask 8′. In this example, anappropriate electrolyte is located between the substrate 6 and the anode12′ and a current of ions coming from one or both of the solution andthe anode are conducted through the opening in the mask to the substratewhere material is deposited. This type of mask may be referred to as ananodeless INSTANT MASK™ (AIM) or as an anodeless conformable contact(ACC) mask.

Unlike through-mask plating, CC mask plating allows CC masks to beformed completely separate from the substrate on which plating is tooccur (e.g. separate from a three-dimensional (3D) structure that isbeing formed). CC masks may be formed in a variety of ways, for example,using a photolithographic process. All masks can be generatedsimultaneously, e.g. prior to structure fabrication rather than duringit. This separation makes possible a simple, low-cost, automated,self-contained, and internally-clean “desktop factory” that can beinstalled almost anywhere to fabricate 3D structures, leaving anyrequired clean room processes, such as photolithography to be performedby service bureaus or the like.

An example of the electrochemical fabrication process discussed above isillustrated in FIGS. 2A-2F. These figures show that the process involvesdeposition of a first material 2 which is a sacrificial material and asecond material 4 which is a structural material. The CC mask 8, in thisexample, includes a patterned conformable material (e.g. an elastomericdielectric material) 10 and a support 12 which is made from depositionmaterial 2. The conformal portion of the CC mask is pressed againstsubstrate 6 with a plating solution 14 located within the openings 16 inthe conformable material 10. An electric current, from power supply 18,is then passed through the plating solution 14 via (a) support 12 whichdoubles as an anode and (b) substrate 6 which doubles as a cathode. FIG.2A illustrates that the passing of current causes material 2 within theplating solution and material 2 from the anode 12 to be selectivelytransferred to and plated on the substrate 6. After electroplating thefirst deposition material 2 onto the substrate 6 using CC mask 8, the CCmask 8 is removed as shown in FIG. 2B. FIG. 2C depicts the seconddeposition material 4 as having been blanket-deposited (i.e.non-selectively deposited) over the previously deposited firstdeposition material 2 as well as over the other portions of thesubstrate 6. The blanket deposition occurs by electroplating from ananode (not shown), composed of the second material, through anappropriate plating solution (not shown), and to the cathode/substrate6. The entire two-material layer is then planarized to achieve precisethickness and flatness as shown in FIG. 2D. After repetition of thisprocess for all layers, the multi-layer structure 20 formed of thesecond material 4 (i.e. structural material) is embedded in firstmaterial 2 (i.e. sacrificial material) as shown in FIG. 2E. The embeddedstructure is etched to yield the desired device, i.e. structure 20, asshown in FIG. 2F.

Various components of an exemplary manual electrochemical fabricationsystem 32 are shown in FIGS. 3A-3C. The system 32 consists of severalsubsystems 34, 36, 38, and 40. The substrate holding subsystem 34 isdepicted in the upper portions of each of FIGS. 3A-3C and includesseveral components: (1) a carrier 48, (2) a metal substrate 6 onto whichthe layers are deposited, and (3) a linear slide 42 capable of movingthe substrate 6 up and down relative to the carrier 48 in response todrive force from actuator 44. Subsystem 34 also includes an indicator 46for measuring differences in vertical position of the substrate whichmay be used in setting or determining layer thicknesses and/ordeposition thicknesses. The subsystem 34 further includes feet 68 forcarrier 48 which can be precisely mounted on subsystem 36.

The CC mask subsystem 36 shown in the lower portion of FIG. 3A includesseveral components: (1) a CC mask 8 that is actually made up of a numberof CC masks (i.e. submasks) that share a common support/anode 12, (2)precision X-stage 54, (3) precision Y-stage 56, (4) frame 72 on whichthe feet 68 of subsystem 34 can mount, and (5) a tank 58 for containingthe electrolyte 16. Subsystems 34 and 36 also include appropriateelectrical connections (not shown) for connecting to an appropriatepower source (not shown) for driving the CC masking process.

The blanket deposition subsystem 38 is shown in the lower portion ofFIG. 3B and includes several components: (1) an anode 62, (2) anelectrolyte tank 64 for holding plating solution 66, and (3) frame 74 onwhich feet 68 of subsystem 34 may sit. Subsystem 38 also includesappropriate electrical connections (not shown) for connecting the anodeto an appropriate power supply (not shown) for driving the blanketdeposition process.

The planarization subsystem 40 is shown in the lower portion of FIG. 3Cand includes a lapping plate 52 and associated motion and controlsystems (not shown) for planarizing the depositions.

In addition to teaching the use of CC masks for electrodepositionpurposes, the '630 patent also teaches that the CC masks may be placedagainst a substrate with the polarity of the voltage reversed andmaterial may thereby be selectively removed from the substrate. Itindicates that such removal processes can be used to selectively etch,engrave, and polish a substrate, e.g., a plaque.

The '630 patent further indicates that the electroplating methods andarticles disclosed therein allow fabrication of devices from thin layersof materials such as, e.g., metals, polymers, ceramics, andsemiconductor materials. It further indicates that although theelectroplating embodiments described therein have been described withrespect to the use of two metals, a variety of materials, e.g.,polymers, ceramics and semiconductor materials, and any number of metalscan be deposited either by the electroplating methods therein, or inseparate processes that occur throughout the electroplating method. Itindicates that a thin plating base can be deposited, e.g., bysputtering, over a deposit that is insufficiently conductive (e.g., aninsulating layer) so as to enable subsequent electroplating. It alsoindicates that multiple support materials (i.e. sacrificial materials)can be included in the electroplated element allowing selective removalof the support materials.

The '630 patent additionally teaches that the electroplating methodsdisclosed therein can be used to manufacture elements having complexmicrostructure and close tolerances between parts. An example is givenwith the aid of FIGS. 14A-14E of that patent. In the example, elementshaving parts that fit with close tolerances, e.g., having gaps betweenabout 1-5 um, including electroplating the parts of the device in anunassembled, preferably pre-aligned state. In such embodiments, theindividual parts can be moved into operational relation with each otheror they can simply fall together. Once together the separate parts maybe retained by clips or the like.

Another method for forming microstructures from electroplated metals(i.e. using electrochemical fabrication techniques) is taught in U.S.Pat. No. 5,190,637 to Henry Guckel, entitled “Formation ofMicrostructures by Multiple Level Deep X-ray Lithography withSacrificial Metal Layers”. This patent teaches the formation of metalstructure utilizing through mask exposures. A first layer of a primarymetal is electroplated onto an exposed plating base to fill a void in aphotoresist (the photoresist forming a through mask having a desiredpattern of openings), the photoresist is then removed, and a secondarymetal is electroplated over the first layer and over the plating base.The exposed surface of the secondary metal is then machined down to aheight which exposes the first metal to produce a flat uniform surfaceextending across both the primary and secondary metals. Formation of asecond layer may then begin by applying a photoresist over the firstlayer and patterning it (i.e. to form a second through mask) and thenrepeating the process that was used to produce the first layer toproduce a second layer of desired configuration. The process is repeateduntil the entire structure is formed and the secondary metal is removedby etching. The photoresist is formed over the plating base or previouslayer by casting and patterning of the photoresist (i.e. voids formed inthe photoresist) are formed by exposure of the photoresist through apatterned mask via X-rays or UV radiation and development of the exposedor unexposed areas.

The '637 patent teaches the locating of a plating base onto a substratein preparation for electroplating materials onto the substrate. Theplating base is indicated as typically involving the use of a sputteredfilm of an adhesive metal, such as chromium or titanium, and then asputtered film of the metal that is to be plated. It is also taught thatthe plating base may be applied over an initial layer of sacrificialmaterial (i.e. a layer or coating of a single material) on the substrateso that the structure and substrate may be detached if desired. In suchcases after formation of the structure the sacrificial material formingpart of each layer of the structure may be removed along with theinitial sacrificial layer to free the structure. Substrate materialsmentioned in the '637 patent include silicon, glass, metals, and siliconwith protected semiconductor devices. A specific example of a platingbase includes about 150 angstroms of titanium and about 300 angstroms ofnickel, both of which are sputtered at a temperature of 160° C. Inanother example, it is indicated that the plating base may consist of150 angstroms of titanium and 150 angstroms of nickel where both areapplied by sputtering.

Electrochemical Fabrication provides the ability to form prototypes andcommercial quantities of miniature objects, parts, structures, devices,and the like at reasonable costs and in reasonable times. In fact,Electrochemical Fabrication is an enabler for the formation of manystructures that were hitherto impossible to produce. ElectrochemicalFabrication opens the spectrum for new designs and products in manyindustrial fields. Even though Electrochemical Fabrication offers thisnew capability and it is understood that Electrochemical Fabricationtechniques can be combined with designs and structures known withinvarious fields to produce new structures, certain uses forElectrochemical Fabrication provide designs, structures, capabilitiesand/or features not known or obvious in view of the state of the art.

A need exists in various fields for miniature devices having improvedcharacteristics, reduced fabrication times, reduced fabrication costs,simplified fabrication processes, greater versatility in device design,improved selection of materials, improved material properties, more costeffective and less risky production of such devices, and/or moreindependence between geometric configuration and the selectedfabrication process.

Thermal Management

Current and next generation high performance electronic devices arereaching such high heat flux levels that new liquid cooling strategiesare required. To tackle this problem, liquid cooled micro-heatexchangers have been in development for some time though they have notseen wide commercial penetration. One reason for this is that these nextgeneration micro-cooling systems with complex inner geometries requireequally complex manufacturing technologies in order to fabricate them.This being the case, many micro-cooling concepts have beenconceptualized using CFD modelling tools though they cannot beimplemented without appropriate manufacturing technology to realize themphysically.

SUMMARY OF THE INVENTION

Some embodiments of the invention are directed to heat transfer arraysthat may be placed in contact with or in proximity to operatingsemiconductors to provide enhanced cooling or heat dissipation. Theseheat transfer arrays may take the form of microjet arrays, hybridmicrochannel microjet arrays, integrated fin and microjet arrays, andeven hybrid microchannel and integrated fin and microjet arrays. Incombination with appropriate inlet and outlet headers and or manifoldsthese heat transfer arrays might be called cold plates or active heatsinks. In combination with pumps, heat exchangers, appropriatefunctional connections (e.g. tubing, channels), optional filters,optional sensors (e.g. pressure, temperature, flow, and the like), andoptional storage reservoirs, and the like these cold plates become(individually or in groups) may form thermal management control systems.

In some embodiments, heat transfer arrays and their formation takeadvantage of the unmatched heat transfer coefficients and surfacetemperature uniformity associated with impinging microjets arraystogether with the high surface area per unit volume associated withmicrochannels as can be implemented using multi-layer, multi-materialelectrochemical deposition (i.e. electrodeposition or electrolessdeposition) methods. Heat transfer arrays and inlet and outlet header ormanifold design may be modeled using computational fluid dynamics (CFD)using, for example ANSYS Fluent Version 16.2 in combination with thecapabilities of Microfabrica's MICA Freeform process. In someembodiments an extreme target heat flux of 1000 W/cm2 was consideredalong with a maximum surface temperature of 65° C. and a maximum surfacetemperature variation of below 10° C. Hydraulically, pressure drop wasconsidered along with an overall volumetric flow rate limitation of 0.5L/min for a 4 mm×4 mm package. In some embodiments, the heat transferarray was simulated using single phase laminar flow solver in Fluent andsimulation of inlet ant outlet headers. The simulations weremulti-physics in nature as they included the heat flow throughout theinternal sold metallic structures as well as the thermal field withinthe fluid. The designs of some embodiments, as simulated achieved theirdesign goals, with a surface average heat transfer coefficient of 360kW/m²K, for a flow rate of 0.5 L/min, and pressure drop of 1 atm. Withan imposed heat flux of 1000 W/cm2 this translates into a maximumsurface temperature less than 58° C. and a surface temperature variationas small as 6° C.

It is an object of some embodiments of the invention to provide animproved micro-scale or millimeter scale thermal management devicesincluding a variation of liquid (e.g. water) cooled heat transferarrays.

It is an object of some embodiments of the invention to provide for thefabrication of such heat transfer array devices using multi-layermulti-material electrochemical fabrication methods.

Other objects and advantages of various embodiments of the inventionwill be apparent to those of skill in the art upon review of theteachings herein. The various embodiments of the invention, set forthexplicitly herein or otherwise ascertained from the teachings herein,may address one or more of the above objects alone or in combination, oralternatively may address some other object ascertained from theteachings herein. It is not necessarily intended that all objects beaddressed by any single aspect of the invention even though that may bethe case with regard to some aspects.

In a first aspect of the invention, a microjet heat transfer array,comprises: (a) a plurality of microjet structures for directing fluidfrom at least one group inlet onto at least one surface of a primaryheat exchange region, wherein the primary heat exchange region isselected from the group consisting of: (1) a surface of a heat source ora plurality of separated surfaces of a heat source, (2) at least onesurface in proximity to one or more heat source surfaces wherein aseparation distance between the at least one surface onto which jettingoccurs and a surface or a plurality of separate surfaces of a heatsource is selected from the group consisting of (i) <=200 um, (ii) <=100um, (iii) <=50 um, (iv) <=20 um, and (v) <=10 um; (3) at least onesurface of a solid material separated from a surface or a plurality ofseparate surfaces of a heat source by a gap that is occupied by at leastone highly conductive transfer material that may be a different solid, asemi-liquid, or a liquid wherein a thickness of the gap is selected fromthe group consisting of (i) <=200 um, (ii) <=100 um, (iii) <=50 um, (iv)<=20 um, and (v) <=10 um, and (4) at least one surface of a solid thatis in intimate contact with a surface or a plurality of separatesurfaces of a heat source; and (b) a plurality of post jetting flowpaths to direct the fluid from the primary heat exchange region to atleast one group outlet, wherein the at least one surface of the primaryheat exchange region onto which jetting occurs is closer, in the jettingdirection, to the surface or the plurality of separate surfaces of theheat source than are the plurality of post jetting flow paths.

In a second aspect of the invention, a hybrid microjet and microchannelheat transfer array, comprises: (a) a plurality of microjet structuresfor directing a heat transfer fluid from at least one group inlet ontoat least one surface of a primary heat exchange region selected from thegroup consisting of: (1) a surface of a heat source or a plurality ofseparated surfaces of a heat source, (2) at least one surface inproximity to one or more heat source surfaces wherein a separationdistance between the at least one surface onto which jetting occurs anda surface or a plurality of separate surfaces of a heat source isselected from the group consisting of (i) <=200 um, (ii) <=100 um, (iii)<=50 um, (iv) <=20 um, and (v) <=10 um; (3) at least one surface of asolid material separated from a surface or a plurality of separatesurfaces of a heat source by a gap that is occupied by at least onehighly conductive transfer material that may be a different solid, asemi-liquid, or a liquid wherein a thickness of the gap is selected fromthe group consisting of (i) <=200 um, (ii) <=100 um, (iii) <=50 um, (iv)<=20 um, and (v) <=10 um), and (4) at least one surface of a solid thatis in intimate contact with a surface or a plurality of separatesurfaces of a heat source; and (b) a plurality of post jettingmicrochannel flow paths to direct the heat transfer fluid from theprimary heat exchange region to at least one group outlet, wherein theat least one surface of the primary heat exchange region onto whichjetting occurs is closer, in the jetting direction, to the surface orthe plurality of separate surfaces of the heat source than are themicrochannel flow paths.

Numerous variations of the first and second aspects of the inventionexist and include, for example: (1) the array of the second aspectwherein the at least one surface on to which jetting occurs comprises aplurality of jetting well surfaces with each jetting well surfacesurrounded by walls that direct fluid away from the jetting well surfaceinto the microchannel flow paths; (2) the array of the first variationwherein each of the plurality of jetting surfaces is configured todirectly receive jetted fluid from a single jet orifice; (3) the arrayof the second aspect where each of the plurality of jetting surfaces isconfigured to directly receive jetted fluid from a group consisting oftwo or more jet orifices; (4) the array of any of first or secondaspects or first to third variations wherein the jets have elongatedcross-sectional configurations (i.e. in a plane perpendicular to ajetting direction) with a length to width aspect ratio selected from thegroup consisting of (i) <=10 to 1, (ii) <=5 to 1, (iii) <=3 to 1, or(iv) <=2 to 1; (5) the array of the fourth variation wherein the lengthof the elongated cross-sectional configurations have an orientation thatextends parallel to a primary flow direction of the fluid as the fluidflows from an inlet to the plurality of microjets; (6) the array of thesecond aspect, or any of the first to fifth variations as they dependdirectly or indirectly from the second aspect wherein the microchannelsdirect fluid received from the jetting structures along paths that flowpast outside walls of the microjet structures initially in a directionthat is substantially anti-parallel to the direction of jetting and thenin a direction that is substantially perpendicular to the direction ofjetting; (7) the array of the first variation, or any of second to sixthvariations as they depend from the first variation, wherein the inlet isspaced further from the surface on to which jetting occurs than does aflow path through the microchannels after the fluid leaves the jettingwells; (8) the array of any of the first or second aspects or first toseventh variations wherein the device is configured to interface with aheat source that comprises a semiconductor device; (9) the array of anyof the first or second aspects or first to eighth variations wherein thedevice comprises a component selected from the group consisting of (A)an IC; (B) a microprocessor; (C) an SOC; (D) an RFIC, e.g. an RFtransmitter or RF receiver; (E) an optical transmitter or receiver; (F)a power amplifier; (G) a GPU; (H) a CPU; (I) a DSP; (J) an ASIC; (K) anAPU; (L) an LED; (M) a laser diode; (N) a power electronic device, e.g.a power inverter or a power converter; (O) a photonic device, (P) apropulsion system; (Q) a solar array, e.g. for a micro satellite; (R) aradiator, e.g. for a micro satellite; (S) an engine of a micro drone;(T) a spacecraft component such as an SSPA; (U) a traveling wave tubeamplifier; (V) a package that holds one or more of the devices of(A)-(T), and (W) a stack or plurality of stacks of devices sandwichedbetween separated heat transfer arrays or interleaved with multiple heattransfer arrays; (10) the array of either of the first or second aspectsany of variations (1)-(7) wherein the density of jets is variesspatially, at least in part, based on spatial heat generation of thesemiconductor device, wherein the jetting structures are placedlaterally closer together in the regions where average heat productionis highest compared to areas where heat production is lowest; (11) thearray of any variations (8), or (9) or (10) as they depend fromvariation (8), wherein the majority of the heat exchange from a solid tothe fluid occurs via a surface of a first metal and wherein selectedportions of the array are formed from a second metal of higher thermalconductive than the first metal such that heat conductivity has a wholeis improved relative to the heat conductivity if the second metal werereplaced with the first metal; (12) the array of either aspect (1) or(2) or variations (1) to (11) wherein regions on to which jetted fluidimpinges are strengthened with a material different from that used toform the side walls of the jetting structures; (13) the array of eitheraspect (1) or (2) or variations (1) to (12) wherein the array comprisesa plurality of adhered planar layers of at least one material wheresuccessive layers can be distinguished by stair-stepped configurationsand wherein layers extend laterally in a cross-sectional dimension and alayer stacking axis is substantially perpendicular to a direction offluid jetting; (14) the array of either aspect (1) or (2) or variations(1) to (13) wherein the heat to be removed requires a heat flux, from atleast a portion of the primary heat transfer region, selected from thegroup consisting of (i) >=200 W/cm², (ii) >=400 W/cm² and (iii) >=800W/cm²); (15) the array of either aspect (1) or (2) or variations (1) to(14) wherein the temperature of the surface or the plurality of separatesurfaces of the heat source are to be held to a temperature selectedfrom the group consisting of (i) <=100° C., (ii) <=80° C., and (iii)<=65° C.; (16) the array of either aspect (1) or (2) or variations (1)to (15) wherein a variation in temperature over the surface or theplurality of surfaces of the heat source is to be held a temperatureselected from the group consisting of (i) <=20° C., (ii) <=15° C., and(iii) <=10° C.; (17) the array of either aspect (1) or (2) or variations(1) to (16) wherein a flow of the heat transfer fluid through the arrayis selected from the group consisting of (i) <=2.0 L/min per 4 mm×4 mmarea covered by the array, (ii) <=1 L/min per 4 mm×4 mm area covered bythe array, and (iii) <=0.5 L/min per 4 mm×4 mm area covered by thearray; (18) the array of either aspect (1) or (2) or variations (1) to(17) wherein the heat source has a surface area covered by the arrayselected from the group consisting of (i) <=900 sq mm, (ii) <=400 sq mm,(iii) <=100 sq mm, (iv) <=25 sq. mm, (v) <=20 sq. mm, and (vi)<=16 sq.mm; (19) the array of aspect 2, and the first-eighteenth variations asthey depend directly or indirectly from aspect 2 wherein at least aportion of the plurality of microjetting structures provide flow pathswith a cross-sectional dimension in the range of 15 to 300 um and morepreferably in the range of 30-200 um; (20) the array the second aspector any of the first to nineteenth variations as they depend directly orindirectly from aspect 2 wherein at least a portion of the post jettingmicrochannels have a cross-sectional dimension in the range of 15-300 umand more preferably in the range of 30-150 um; (21) the array of eitherthe first or second aspects or any of the first to twentieth variationswherein distal ends of a plurality of jetting structures are spaced fromthe at least one surface of the primary heat exchange region by lengthin the range of 15-200 um and preferably in the range of 30-100 um; (22)the array of either the first or second aspect or any of the first totwenty-first variations wherein a first height of at least a pluralityof post jetting microchannels is in the range of 40 to 600 um and morepreferably in the range of 80-300 um, and wherein the first height ismeasured along a portion of the microchannels that directs fluid flow ina direction substantially anti-parallel to a direction of flow of fluidthrough the jetting structures; (23) the array of either the first orsecond aspect and any of the first to twenty-second variations wherein aheight of at least a plurality of the jetting structures is in the rangeof 300 um to 1 mm and more preferably in the range of 400-800 um; (24)the array of either the first or second aspect or any of the first totwenty-third variations wherein a height of at least a plurality of thejets is in the range of 300 um to 1 mm and more preferably in the rangeof 400-800 um wherein a second height of at least a plurality of postjetting microchannels is in the range of 300-2000 um and more preferablyin the range of 600-1000 um, wherein the second height is measured alonga portion of the microchannels that directs fluid flow in a directionsubstantially perpendicular to the direction of flow of fluid throughthe jetting structures; (25) the array of either the first or secondaspect or any of the first to twenty-fourth variations wherein a jettingwell height extends from the at least one surface of the primary heatexchange region to a height that is above a height at which fluid exitsthe jetting structures; (26) the array of either the first or secondaspect or any of the first to twenty-fifth variations wherein the arrayis configured to use a heat transfer fluid that is a liquid; (27) thearray of the twenty-sixth variation wherein the liquid comprises water;(28) The array of either the twenty-sixth or twenty-seventh variationwherein the water does not undergo a phase change during a process ofcooling a semiconductor; (29) the array of either the first or secondaspect and any of the first to twenty-eighth variations wherein a solidmaterial separating two adjacent jetting wells comprises a core materialsurrounded at least partially by a shell material wherein the corematerial has a higher thermal conductivity than does the shell materialand also has a lower yield strength; or (30) the array of either thefirst or second aspect or any of the first to twenty-ninth variationswherein the plurality of jetting structures function as fins thatcontact the at least one surface of the at least one primary heatexchange region whereby a lowest portion of the plurality of jettingstructures is in solid-to-solid contact with the at least one surface ofthe primary heat exchange region while at least one opening exists inthe jetting structures above the at least one surface of the primaryheat exchange region such that the jetted fluid is free from anenclosing jetting channel within the jetting structure to impinge on theat least one surface of the primary heat exchange region.

In a third aspect of the invention, a microjet heat transfer array,comprises: (a) plurality of fins with each fin providing an embeddedmicrojet for directing fluid from at least one group inlet onto at leastone surface of a primary heat exchange region selected from the groupconsisting of: (1) a surface of a heat source or a plurality ofseparated surfaces of a heat source, (2) at least one surface inproximity to one or more heat source surfaces wherein a separationbetween the at least one surface onto which jetting occurs and a surfaceor a plurality of surfaces of a heat source is selected from the groupconsisting of (i) <=200 um, (ii) <=100 um, (iii) <=50 um, (iv) <=20 um,and (v) <=10 um; (3) at least one surface of a solid material separatedfrom a surface or a plurality of separate surfaces of a heat source by agap that is occupied by at least one highly conductive transfer materialthat may be a different solid, a semi-liquid, or a liquid wherein athickness of the gap is selected from the group consisting of (i), =200um, (ii) <=100 um, (iii) <=50 um, (iv) <=20 um, and (v) <=10 um), and(4) at least one surface of a solid that is in intimate contact with asurface or a plurality of separate surfaces of a heat source; (b) aplurality of post jetting microchannel flow paths to direct the fluidfrom the primary heat exchange region to at least one group outlet,wherein the plurality of fins provide a solid conductive heat flow pathfrom the at least one surface onto which jetting occurs.

Numerous variations of the third aspect exist including, for example:(1) the array of the third aspect wherein the surface onto which jettingoccurs is closer, in the jetting direction, to the heat source than arethe plurality of post jetting microchannel flow paths; (2) the array ofthe third aspect wherein each fin provides a plurality of conductivesolid contact paths directly to the surface of the primary heat exchangeregion onto which jetting occurs; or (3) the array of the third aspectwherein each fin has an elongated cross-sectional configuration. Othervariations are similar to those noted for the first and second aspectsof the invention so long as those variations do not contradict orotherwise nullify the features of the third aspect.

In a fourth aspect of the invention, a micro cold plate, comprises: (a)at least one group fluid inlet; (b) at least one group fluid outlet; (c)a microjet heat transfer array, comprising: (1) a plurality of microjetstructures for directing fluid from at least one group fluid inlet ontoat least one surface of a primary heat exchange region, wherein theprimary heat exchange region is selected from the group consisting of:(A) a surface of a heat source or a plurality of separated surfaces of aheat source, (B) at least one surface in proximity to one or more heatsource surfaces wherein a separation distance between the at least onesurface onto which jetting occurs and a surface or a plurality ofseparate surfaces of a heat source is selected from the group consistingof (i) <=200 um, (ii) <=100 um, (iii) <=50 um, (iv) <=20 um, and (v)<=10 urn; (C) at least one surface of a solid material separated from asurface or a plurality of separate surfaces of a heat source by a gapthat is occupied by at least one highly conductive transfer materialthat may be a different solid, a semi-liquid, or a liquid wherein athickness of the gap is selected from the group consisting of (i) <=200um, (ii) <=100 um, (iii) <=50 um, (iv) <=20 um, and (v) <=10 um, and (D)at least one surface of a solid that is in intimate contact with asurface or a plurality of separate surfaces of a heat source; and (2) aplurality of post jetting flow paths to direct the fluid from theprimary heat exchange region to at least one group fluid outlet, whereinthe at least one surface of the primary heat exchange region onto whichjetting occurs is closer, in the jetting direction, to the surface orthe plurality of separate surfaces of the heat source than are theplurality of post jetting flow paths.

In a fifth aspect of the invention, a micro cold plate, comprises: (a)at least one group fluid inlet; (b) at least one group fluid outlet; (c)a hybrid microjet and microchannel heat transfer array, comprising: (1)a plurality of microjet structures for directing a heat transfer fluidfrom the at least one group fluid inlet onto at least one surface of aprimary heat exchange region selected from the group consisting of: (A)a surface of a heat source or a plurality of separated surfaces of aheat source, (B) at least one surface in proximity to one or more heatsource surfaces wherein a separation distance between the at least onesurface onto which jetting occurs and a surface or a plurality ofseparate surfaces of a heat source is selected from the group consistingof (i) <=200 um, (ii) <=100 um, (iii) <=50 um, (iv) <=20 um, and (v)<=10 urn; (C) at least one surface of a solid material separated from asurface or a plurality of separate surfaces of a heat source by a gapthat is occupied by at least one highly conductive transfer materialthat may be a different solid, a semi-liquid, or a liquid wherein athickness of the gap is selected from the group consisting of (i) <=200um, (ii) <=100 um, (iii) <=50 um, (iv) <=20 um, and (v) <=10 urn), and(D) at least one surface of a solid that is in intimate contact with asurface or a plurality of separate surfaces of a heat source; and (2) aplurality of post jetting microchannel flow paths to direct the heattransfer fluid from the primary heat exchange region to at least onegroup fluid outlet, wherein the at least one surface of the primary heatexchange region onto which jetting occurs is closer, in the jettingdirection, to the surface or the plurality of separate surfaces of theheat source than are the microchannel flow paths.

Numerous variations of the fourth and fifth aspects of the inventionexist. Some such variations are analogous to the variations of the firstand second aspects as well as to variations of those variations, mutatismutandis, for example where the variation would apply to a cold plate asopposed to a heat transfer array.

In a sixth aspect of the invention, a micro cold plate, comprises: (a)at least one group fluid inlet; (b) at least one group fluid outlet; (c)a microjet heat transfer array, comprising: (1) plurality of fins witheach fin providing an embedded microjet for directing fluid from the atleast one group fluid inlet onto at least one surface of a primary heatexchange region selected from the group consisting of: (A) a surface ofa heat source or a plurality of separated surfaces of a heat source, (B)at least one surface in proximity to one or more heat source surfaceswherein a separation between the at least one surface onto which jettingoccurs and a surface or a plurality of surfaces of a heat source isselected from the group consisting of (i) <=200 um, (ii) <=100 um, (iii)<=50 um, (iv) <=20 um, and (v) <=10 um; (C) at least one surface of asolid material separated from a surface or a plurality of separatesurfaces of a heat source by a gap that is occupied by at least onehighly conductive transfer material that may be a different solid, asemi-liquid, or a liquid wherein a thickness of the gap is selected fromthe group consisting of (i), =200 um, (ii) <=100 um, (iii) <=50 um, (iv)<=20 um, and (v) <=10 um), and (D) at least one surface of a solid thatis in intimate contact with a surface or a plurality of separatesurfaces of a heat source; and (2) a plurality of post jettingmicrochannel flow paths to direct the fluid from the primary heatexchange region to the at least one group fluid outlet, wherein theplurality of fins provide a solid conductive heat flow path from the atleast one surface onto which jetting occurs.

Numerous variations of the sixth aspect of the invention exist. Somesuch variations are analogous to those noted for above for the thirdaspect of the invention, mutatis mutandis, for example where thevariation would apply to a cold plate as opposed to a heat transferarray. Other variations are similar to those noted for the fourth andfifth aspects of the invention so long as those variations do notcontradict or otherwise nullify the features of the sixth aspect.

In a seventh aspect of the invention, a thermal management system for asemiconductor device, comprises: (1) at least one micro cold plate,comprising: (a) at least one fluid inlet header or manifold; (b) atleast one fluid outlet header or manifold; (c) a microjet heat transferarray, comprising: (I) a plurality of microjet structures for directingfluid from at least one fluid inlet header or manifold onto at least onesurface of a primary heat exchange region, wherein the primary heatexchange region is selected from the group consisting of: (A) a surfaceof a heat source or a plurality of separated surfaces of a heat source,(B) at least one surface in proximity to one or more heat sourcesurfaces wherein a separation distance between the at least one surfaceonto which jetting occurs and a surface or a plurality of separatesurfaces of a heat source is selected from the group consisting of (i)<=200 um, (ii) <=100 um, (iii) <=50 um, (iv) <=20 um, and (v) <=10 um;(C) at least one surface of a solid material separated from a surface ora plurality of separate surfaces of a heat source by a gap that isoccupied by at least one highly conductive transfer material that may bea different solid, a semi-liquid, or a liquid wherein a thickness of thegap is selected from the group consisting of (i) <=200 um, (ii) <=100um, (iii) <=50 um, (iv) <=20 um, and (v) <=10 um, and (D) at least onesurface of a solid that is in intimate contact with a surface or aplurality of separate surfaces of a heat source; and (II) a plurality ofpost jetting flow paths to direct the fluid from the primary heatexchange region to at least one outlet header or manifold, wherein theat least one surface of the primary heat exchange region onto whichjetting occurs is closer, in the jetting direction, to the surface orthe plurality of separate surfaces of the heat source than are theplurality of post jetting flow paths; (2) at least one flow path to moveheated fluid, directly or indirectly, from the from the fluid outletheader or manifold of the at least one micro cold plate to a heatexchanger; (3) at least one flow path to move cooled fluid, directly orindirectly, from the heat exchanger back into the inlet header ormanifold of the at least one micro cold plate; and (4) at least one pumpfunctionally configured to direct the fluid through the at least onecold plate to the heat exchanger and back to the at least one coldplate.

In an eighth aspect of the invention, a thermal management system for asemiconductor device, comprises: (1) at least one micro cold plate,comprising: (a) at least one fluid inlet header or manifold; (b) atleast one fluid outlet header or manifold; (c) a hybrid microjet andmicrochannel heat transfer array, comprising: (I) a plurality ofmicrojet structures for directing a heat transfer fluid from the atleast one fluid inlet header or manifold onto at least one surface of aprimary heat exchange region selected from the group consisting of: (A)a surface of a heat source or a plurality of separated surfaces of aheat source, (B) at least one surface in proximity to one or more heatsource surfaces wherein a separation distance between the at least onesurface onto which jetting occurs and a surface or a plurality ofseparate surfaces of a heat source is selected from the group consistingof (i) <=200 um, (ii) <=100 um, (iii) <=50 um, (iv) <=20 um, and (v)<=10 um; (C) at least one surface of a solid material separated from asurface or a plurality of separate surfaces of a heat source by a gapthat is occupied by at least one highly conductive transfer materialthat may be a different solid, a semi-liquid, or a liquid wherein athickness of the gap is selected from the group consisting of (i) <=200um, (ii) <=100 um, (iii) <=50 um, (iv) <=20 um, and (v) <=10 um), and(D) at least one surface of a solid that is in intimate contact with asurface or a plurality of separate surfaces of a heat source; and (II) aplurality of post jetting microchannel flow paths to direct the heattransfer fluid from the primary heat exchange region to the at least oneoutlet header or manifold, wherein the at least one surface of theprimary heat exchange region onto which jetting occurs is closer, in thejetting direction, to the surface or the plurality of separate surfacesof the heat source than are the microchannel flow paths; (2) at leastone flow path to move heated fluid, directly or indirectly, from thefrom the fluid outlet header or manifold of the at least one micro coldplate to a heat exchanger; (3) at least one flow path to move cooledfluid, directly or indirectly, from the heat exchanger back into theinlet header or manifold of the at least one micro cold plate; (4) atleast one pump functionally configured to direct the fluid through theat least one cold plate to the heat exchanger and back to the at leastone cold plate.

Numerous variations of the seventh and eighth aspects of the inventionexist. Some such variations are analogous to the variations of the firstand second aspects as well as to variations of those variations, mutatismutandis, for example where the variations would apply to a system asopposed to a heat transfer array. Additional variations, include, forexample: (1) a filter being located along the flow path between theoutlet and the pump; (2) a filter being located along the flow pathbetween pump and the inlet; (3) a filter being located along the flowpath between pump and the heat exchanger; (4) the pump being mounted toa header or manifold of the cold plate; (5) the pump being spaced fromthe cold plate; (6) at least one temperature sensor and a control systemfor turning on the pump when a detected temperature is greater than ahigh temperature set point; (7) at least one temperature sensor and acontrol system for turning off the pump when a detected temperature isless than a low temperature set point; (8) the system comprises aplurality of microjet arrays with at least two of the arrays spaced fromone another to remove heat from separated portions of a singleintegrated circuit; (9) the system comprises a plurality of microjetarrays with at least two of the arrays spaced from one another to removeheat from two different integrated circuits; (10) at least one pressuresensor to monitor fluid pressure in the flow paths; (11) the micro coldplate comprises a single structure that provides both the inlet headeror manifold and the outlet header or manifold.

In a ninth aspect of the invention, a thermal management system for asemiconductor device, comprises: (1) at least one micro cold plate,comprising: (a) at least one fluid inlet header or manifold; (b) atleast one fluid outlet header or manifold; (c) a microjet andmicrochannel heat transfer array, comprising: (I) plurality of fins witheach fin providing an embedded microjet for directing fluid from the atleast one fluid inlet header or manifold onto at least one surface of aprimary heat exchange region selected from the group consisting of: (A)a surface of a heat source or a plurality of separated surfaces of aheat source, (B) at least one surface in proximity to one or more heatsource surfaces wherein a separation between the at least one surfaceonto which jetting occurs and a surface or a plurality of surfaces of aheat source is selected from the group consisting of (i) <=200 um, (ii)<=100 um, (iii) <=50 um, (iv) <=20 um, and (v) <=10 um; (C) at least onesurface of a solid material separated from a surface or a plurality ofseparate surfaces of a heat source by a gap that is occupied by at leastone highly conductive transfer material that may be a different solid, asemi-liquid, or a liquid wherein a thickness of the gap is selected fromthe group consisting of (i), =200 um, (ii) <=100 um, (iii) <=50 um, (iv)<=20 um, and (v) <=10 um), and (D) at least one surface of a solid thatis in intimate contact with a surface or a plurality of separatesurfaces of a heat source; (II) a plurality of post jetting microchannelflow paths to direct the fluid from the primary heat exchange region tothe at least one outlet header or manifold, wherein the plurality offins provide a solid conductive heat flow path from the at least onesurface onto which jetting occurs; (2) at least one flow path to moveheated fluid, directly or indirectly, from the from the fluid outletheader or manifold of the at least one micro cold plate to a heatexchanger; (3) at least one flow path to move cooled fluid, directly orindirectly, from the heat exchanger back into the inlet header ormanifold of the at least one micro cold plate; and (4) at least one pumpfunctionally configured to direct the fluid through the at least onecold plate to the heat exchanger and back to the at least one coldplate.

Numerous variations of the ninth aspect of the invention exist. Somesuch variations are analogous to those noted for above for the thirdaspect of the invention, mutatis mutandis, for example where thevariation would apply to a system as opposed to a heat transfer array.Other variations are similar to those noted for the seventh and eighthaspects of the invention so long as those variations do not contradictor otherwise nullify the features of the ninth aspect.

In a tenth aspect of the invention, a method for the batch formation ofa plurality of heat transfer arrays, comprises: (a) forming plurality ofsuccessively formed layers wherein each successive layer comprises atleast two materials and is formed on and adhered to a previously formedlayer, one of the at least two materials is a structural material andthe other of the at least two materials is a sacrificial material, andwherein the forming of each of the plurality of successive layerscomprises: (i) depositing a first of the at least two materials; (ii)depositing a second of the at least two materials; (iii) planarizing thefirst and second materials to set a boundary level for the layer; and(b) after the forming of the plurality of successive layers, separatingat least a portion of the sacrificial material from multiple layers ofthe structural material to reveal the plurality of heat transfer arrays,wherein the each of the plurality of heat transfer arrays, comprise: (A)a plurality of microjet structures for directing fluid from at least onegroup inlet onto at least one surface of a primary heat exchange region,wherein the primary heat exchange region is selected from the groupconsisting of: (1) a surface of a heat source or a plurality ofseparated surfaces of a heat source; (2) at least one surface inproximity to one or more heat source surfaces wherein a separationdistance between the at least one surface onto which jetting occurs anda surface or a plurality of separate surfaces of a heat source isselected from the group consisting of (i) <=200 urn, (ii) <=100 um,(iii) <=50 um, (iv) <=20 um, and (v) <=10 urn; (3) at least one surfaceof a solid material separated from a surface or a plurality of separatesurfaces of a heat source by a gap that is occupied by at least onehighly conductive transfer material that may be a different solid, asemi-liquid, or a liquid wherein a thickness of the gap is selected fromthe group consisting of (i) <=200 um, (ii) <=100 um, (iii) <=50 um, (iv)<=20 um, and (v) <=10 um, and (4) at least one surface of a solid thatis in intimate contact with a surface or a plurality of separatesurfaces of a heat source; and (B) a plurality of post jetting flowpaths to direct the fluid from the primary heat exchange region to atleast one group outlet, wherein the at least one surface of the primaryheat exchange region onto which jetting occurs is closer, in the jettingdirection, to the surface or the plurality of separate surfaces of theheat source than are the plurality of post jetting flow paths.

In an eleventh aspect of the invention, a method for the batch formationof a plurality of heat transfer arrays, comprises: (a) forming pluralityof successively formed layers wherein each successive layer comprises atleast two materials and is formed on and adhered to a previously formedlayer, one of the at least two materials is a structural material andthe other of the at least two materials is a sacrificial material, andwherein the forming of each of the plurality of successive layerscomprises: (i) depositing a first of the at least two materials; (ii)depositing a second of the at least two materials; (iii) planarizing thefirst and second materials to set a boundary level for the layer; and(b) after the forming of the plurality of successive layers, separatingat least a portion of the sacrificial material from multiple layers ofthe structural material to reveal the plurality of heat transfer arrays,wherein the each of the plurality of heat transfer arrays, comprise: (A)a plurality of microjet structures for directing a heat transfer fluidfrom at least one group inlet onto at least one surface of a primaryheat exchange region selected from the group consisting of: (1) asurface of a heat source or a plurality of separated surfaces of a heatsource; (2) at least one surface in proximity to one or more heat sourcesurfaces wherein a separation distance between the at least one surfaceonto which jetting occurs and a surface or a plurality of separatesurfaces of a heat source is selected from the group consisting of (i)<=200 um, (ii) <=100 um, (iii) <=50 um, (iv) <=20 um, and (v) <=10 urn;(3) at least one surface of a solid material separated from a surface ora plurality of separate surfaces of a heat source by a gap that isoccupied by at least one highly conductive transfer material that may bea different solid, a semi-liquid, or a liquid wherein a thickness of thegap is selected from the group consisting of (i) <=200 um, (ii) <=100um, (iii) <=50 um, (iv) <=20 um, and (v) <=10 um), and (4) at least onesurface of a solid that is in intimate contact with a surface or aplurality of separate surfaces of a heat source; and (B) a plurality ofpost jetting microchannel flow paths to direct the heat transfer fluidfrom the primary heat exchange region to at least one group outlet,wherein the at least one surface of the primary heat exchange regiononto which jetting occurs is closer, in the jetting direction, to thesurface or the plurality of separate surfaces of the heat source thanare the microchannel flow paths.

Numerous variations of the tenth and eleventh aspects of the inventionexist. Some such variations are analogous to the variations of the firstand second aspects as well as to variations of those variations, mutatismutandis, for example where the variations would apply to a method forfabricating a heat transfer array as opposed to a heat transfer arrayitself.

In a twelfth aspect of the invention, a method for the batch formationof a plurality of heat transfer arrays, comprises: (a) forming pluralityof successively formed layers wherein each successive layer comprises atleast two materials and is formed on and adhered to a previously formedlayer, one of the at least two materials is a structural material andthe other of the at least two materials is a sacrificial material, andwherein the forming of each of the plurality of successive layerscomprises: (i) depositing a first of the at least two materials; (ii)depositing a second of the at least two materials; (iii) planarizing thefirst and second materials to set a boundary level for the layer; and(b) after the forming of the plurality of successive layers, separatingat least a portion of the sacrificial material from multiple layers ofthe structural material to reveal the plurality of heat transfer arrays,wherein the each of the plurality of heat transfer arrays, comprise: (A)plurality of fins with each fin providing an embedded microjet fordirecting fluid from at least one group inlet onto at least one surfaceof a primary heat exchange region selected from the group consisting of:(1) a surface of a heat source or a plurality of separated surfaces of aheat source, (2) at least one surface in proximity to one or more heatsource surfaces wherein a separation between the at least one surfaceonto which jetting occurs and a surface or a plurality of surfaces of aheat source is selected from the group consisting of (i) <=200 um, (ii)<=100 um, (iii) <=50 um, (iv) <=20 um, and (v) <=10 um; (3) at least onesurface of a solid material separated from a surface or a plurality ofseparate surfaces of a heat source by a gap that is occupied by at leastone highly conductive transfer material that may be a different solid, asemi-liquid, or a liquid wherein a thickness of the gap is selected fromthe group consisting of (i), =200 um, (ii) <=100 um, (iii) <=50 um, (iv)<=20 um, and (v) <=10 um), and (4) at least one surface of a solid thatis in intimate contact with a surface or a plurality of separatesurfaces of a heat source; and (B) a plurality of post jettingmicrochannel flow paths to direct the fluid from the primary heatexchange region to at least one group outlet, wherein the plurality offins provide a solid conductive heat flow path from the at least onesurface onto which jetting occurs.

Numerous variations of the twelfth aspect of the invention exist. Somesuch variations are analogous to those noted above for the third aspectof the invention, mutatis mutandis, for example where the variationwould apply to a method of fabrication as opposed to a heat transferarray. Other variations are similar to those noted for the tenth andeleventh aspects of the invention so long as those variations do notcontradict or otherwise nullify the features of the twelfth aspect.Still further variations include, for example: (1) the array beingconfigured to use a heat transfer fluid that is a liquid; (2) where theliquid of the first further variation comprises water; or (3) whereinthe liquid of the first or second further variation does not undergo aphase change during a process of cooling a semiconductor.

In a thirteenth aspect of the invention, a method for the batchformation of a plurality of heat transfer arrays, comprises: (a) formingplurality of successively formed layers wherein each successive layercomprises at least two materials and is formed on and adhered to apreviously formed layer, one of the at least two materials is astructural material and the other of the at least two materials is asacrificial material, and wherein the forming of each of the pluralityof successive layers comprises: (i) depositing a first of the at leasttwo materials; (ii) depositing a second of the at least two materials;(iii) planarizing the first and second materials to set a boundary levelfor the layer; and (b) after the forming of the plurality of successivelayers, separating at least a portion of the sacrificial material frommultiple layers of the structural material to reveal the plurality ofheat transfer arrays, wherein the each of the plurality of heat transferarrays, comprises features selected from the group consisting of: (1) amicrojet array, (2) a plurality of microjet structures and microchannelsthat receive fluid after being jetted from jetting structures, and (3) aplurality of fins and microjet structures wherein the fins comprise atleast a portion of the jetting structures including jetting channels andjetting orifices.

Numerous variations of the thirteenth aspect of the invention exist.Some such variations are analogous to those noted above for the first toninth aspects of the invention, mutatis mutandis, for example where thevariation would apply to a method of fabrication as opposed to a heattransfer array. Other variations are similar to those noted for thetenth to twelfth aspects of the invention so long as those variations donot contradict or otherwise nullify the features of the thirteenthaspect. Still further variations include, for example: (1) the methodfurther comprising: (c) designing a 3D representation of the heattransfer array in 3D CAD, (d) dividing the representation into aplurality of stacked layer representations of representing successivecross-sections of the heat transfer array, and (e) providing furtherprocessing of the cross-sectional data to derive fabrication data forthe heat transfer array, wherein the fabrication data is used increating the successively formed layers; (2) wherein the array isconfigured to use a heat transfer fluid that is a liquid; (3) the liquidof the second further variation comprises water; (4) the array isconfigured such that the liquid of the second or third further variationdoes not undergo a phase change during a process of cooling asemiconductor; (5) the heat transfer array is formed primarily of one ormore metals; (6) a metal of fifth further variation is deposited byelectrodeposition.

In a fourteenth aspect of the invention, a method for the formation of amicro cold plate for semiconductor cooling, comprises: (a) forming aheat transfer array comprising: (1) forming a plurality of successivelyformed layers, wherein each successive layer comprises at least twomaterials and is formed on and adhered to a previously formed layer, oneof the at least two materials is a structural material and the other ofthe at least two materials is a sacrificial material, and wherein eachsuccessive layer defines a successive cross-section of thethree-dimensional structure, and wherein the forming of each of theplurality of successive layers comprises: (i) depositing a first of theat least two materials; (ii) depositing a second of the at least twomaterials; (iii) planarizing the first and second materials to set aboundary level for the layer; and (2) after the forming of the pluralityof successive layers, separating at least a portion of the sacrificialmaterial from multiple layers of the structural material to reveal thethree-dimensional parts; (b) supplying a fluid inlet in the form of aheader or manifold and a fluid outlet in the form of a header ormanifold; and (c) attaching the microjet array to the fluid inlet andfluid outlet, wherein the each of the heat transfer array, comprisesfeatures selected from the group consisting of: (1) a microjet array,(2) a plurality of microjet structures and microchannels that receivefluid after being jetted from jetting structures, and (3) a plurality offins and microjet structures wherein the fins comprise at least aportion of the jetting structures including jetting channels and jettingorifices.

Numerous variations of the fourteenth aspect of the invention exist.Some such variations are analogous to those noted above for the first toninth aspects of the invention, mutatis mutandis, for example where thevariation would apply to a method of fabrication as opposed to a heattransfer array. Other variations are similar to those noted for thetenth to thirteen aspects of the invention so long as those variationsdo not contradict or otherwise nullify the features of the fourteenthaspect.

In a fifteenth aspect of the invention, a method for forming a thermalmanagement control system for semiconductor cooling, comprises: (a)forming at least one heat transfer array comprising: (1) forming aplurality of successively formed layers, wherein each successive layercomprises at least two materials and is formed on and adhered to apreviously formed layer, one of the at least two materials is astructural material and the other of the at least two materials is asacrificial material, and wherein each successive layer defines asuccessive cross-section of the three-dimensional structure, and whereinthe forming of each of the plurality of successive layers comprises: (i)depositing a first of the at least two materials; (ii) depositing asecond of the at least two materials; (iii) planarizing the first andsecond materials to set a boundary level for the layer; and (2) afterthe forming of the plurality of successive layers, separating at least aportion of the sacrificial material from multiple layers of thestructural material to reveal the three-dimensional part; (b) supplyingat least one fluid inlet in the form of a header or manifold and atleast one fluid outlet in the form of a header or manifold; (c)providing at least one semiconductor device, at least one heat exchange,and at least one pump; (d) attaching the at least one microjet array tothe at least one fluid inlet and at least one fluid outlet; (e)functionally coupling the semiconductor device and the microjet array;(f) providing and functionally connecting at least one flow path to moveheated fluid, directly or indirectly, from the from the fluid outletheader or manifold to a heat exchanger; (g) providing and functionallyconnecting at least one flow path to move cooled fluid, directly orindirectly, from the heat exchanger back into the inlet header ormanifold; and (h) providing and functionally connecting at least onepump to direct the fluid through the at least one cold plate to the heatexchanger and back to the at least one cold plate, wherein the each ofthe heat transfer array, comprises features selected from the groupconsisting of: (A) a microjet array, (B) a plurality of microjetstructures and microchannels that receive fluid after being jetted fromjetting structures, and (C) a plurality of fins and microjet structureswherein the fins comprise at least a portion of the jetting structuresincluding jetting channels and jetting orifices.

Numerous variations of the fifteenth aspect of the invention exist. Somesuch variations are analogous to those noted above for the first toninth aspects of the invention, mutatis mutandis, for example where thevariation would apply to a method of fabrication as opposed to a heattransfer array. Other variations are similar to those noted for thetenth to fourteenth aspects of the invention so long as those variationsdo not contradict or otherwise nullify the features of the fifteenthaspect.

In a sixteenth aspect of the invention, a method of cooling asemiconductor device, comprises: (a) providing at least one heattransfer array, comprising a plurality of stacked and adhered layerscomprising at least one metal wherein the each of the at least one heattransfer array comprises features selected from the group consisting of:(1) a microjet array, (2) a plurality of microjet structures andmicrochannels that receive fluid after being jetted from jettingstructures, and (3) a plurality of fins and microjet structures whereinthe fins comprise at least a portion of the jetting structures includingjetting channels and jetting orifices. (b) placing the heat transferarray in physical contact with or in proximity to the semiconductordevice to be cooled to form a primary heat transfer region having atleast one cooling fluid impingement surface; (c) pumping a cooling fluidinto at least one inlet of the heat transfer array such that the coolingfluid is jetted onto the impingement surface to extract heat therefrom,then passing the heated cooling fluid to at least one outlet of the heattransfer array, while continuing to extract heat from the heat transferarray, and then on to a heat exchanger where heat is removed from thecooling fluid to produce cooled cooling fluid; (d) circulating thecooled cooling fluid from the heat exchanger back into the at least oneinlet array of the heat transfer array to repeat a flow cycle to drawheat from the at least one semiconductor device.

Numerous variations of the fifteenth aspect of the invention exist. Somesuch variations provide added features similar to those found in theprevious aspects of the invention or in their variations. In some suchvariations the array is configured to use a heat transfer fluid that isa liquid, in others the liquid may be water, and in still others thecooling process may be provided to remove heat from a semiconductordevice.

In other aspects of the invention the heat transfer arrays may not bemicroscale or millimeter scale devices but instead macroscale devicesthat provide cooling of large scale structures and devices such asinternal combustion engine blocks, jet engines, rocket engines, varioushigh heat transfer components of engines, combustion chambers, powerconverters, electrical resistors, batteries, light sources, lasers, andthe like. Such macroscale heat transfer arrays may be fabricated byvarious methods including traditional machining and assembly methods oradditive fabrication methods such as stereolithography and casting,selective laser sintering, and other direct and indirect metaldeposition methods. In some such embodiments, heat transfer arrayfeatures, fluid channels, jet diameters, well sizes, fluid flow rates,and the like may be scaled with the device size or may retainmicro-scale or millimeter scale dimensions as appropriate. In some suchembodiments, the dimensions set forth herein for some devices' featuresmay vary from those set forth while ratios of at least some dimensionsmay scale.

Other aspects of the invention will be understood by those of skill inthe art upon review of the teachings herein. These other aspects of theinvention may provide various combinations of the aspects presentedabove as well as provide other configurations, structures, functionalrelationships, and processes that have not been specifically set forthabove.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1C schematically depict side views of various stages of a CCmask plating process, while FIGS. 1D-1G schematically depict side viewsof various stages of a CC mask plating process using a different type ofCC mask.

FIGS. 2A-2F schematically depict side views of various stages of anelectrochemical fabrication process as applied to the formation of aparticular structure where a sacrificial material is selectivelydeposited while a structural material is blanket deposited.

FIGS. 3A-3C schematically depict side views of various examplesubassemblies that may be used in manually implementing theelectrochemical fabrication method depicted in FIGS. 2A-2F.

FIGS. 4A-4F schematically depict the formation of a first layer of astructure using adhered mask plating where the blanket deposition of asecond material overlays both the openings between deposition locationsof a first material and the first material itself.

FIG. 4G depicts the completion of formation of the first layer resultingfrom planarizing the deposited materials to a desired level.

FIGS. 4H and 4I respectively depict the state of the process afterformation of the multiple layers of the structure and after release ofthe structure from the sacrificial material.

FIG. 5 provides a schematic view of a thermal management system (e.g. acooling system) that includes a thermal management device in the form ofa cold plate that includes at least one thermal transfer array and inletand outlet headers or manifolds.

FIG. 6 provides a schematic view of an alternative thermal managementsystem (e.g. a cooling system) that includes a thermal management device(e.g. a cold plate that includes a heat transfer array in combinationwith separately formed inlet and outlet headers or manifolds).

FIG. 7 provides a perspective view of an example cold plate with itscover removed that includes an integrated microchannel and microjetarray (heat transfer array) wherein the heat source (not shown) is to bepositioned below the array and wherein cooling fluid (e.g. water) flowsin from the left side of the device over the baffle plate and then intothe slot jets to extract heat from the source and then finally flows outthrough the outlet on the right side of the device.

FIG. 8 provides a cut perspective view of the cold plate with anintegrated heat transfer array and inlet/outlet system such that theinlet, the baffle plate, baffle elements, jets, and post jetting flowchannels and outlet can be seen.

FIG. 9 provides a perspective view of an example cold plate similar tothat of FIGS. 7-8 where a portion of the baffle plate and fluid flowlines showing some possible fluid flow paths through an inlet layer orregion around the baffle elements can be seen.

FIG. 10 provides a cut side view of several jet elements having wallsand orifices of a device similar to the devices of FIGS. 7-9 such thatinside channels of the jets, flow paths through the jets, and fluidimpact regions below the jets can be seen, wherein a heat source, to becooled, would be located below the heat transfer region at the bottom ofthe figure.

FIG. 11 provides a cut view of a single microjet region of a devicealong with some sample dimensional ranges that might be used in someembodiments.

FIG. 12 provides a cut top view of the baffle plate along with somesample dimensions for the jet, baffles, and spacing between baffleelements.

FIG. 13 provides another perspective cut view of a single jet regionwhere the post jetting flow regions along the well walls include solidfin elements and channels to provide additional surface area foroptimizing heat transfer.

FIG. 14 provides a chart illustrating the anticipated performanceenhancement that may be achievable by some embodiments of the presentinvention where microchannels or optimized microchannels and microjetarrays are combined for improved thermal conductance, decreased pressuredrop across the heat transfer array, and improved heat flux through theheat transfer array.

FIG. 15 provides a perspective view of the top of an alternative coldplate (i.e. heat transfer array and inlet/outlet combination) with thecover in place and with the inlet moved from the left side to the topand with the single outlet of FIG. 7 modified into two outlets with oneon the left and one on the right.

FIG. 16 provides a perspective view of the top of another alternativecold plate, with the cover removed, and with the cylindrical baffleelements replaced by triangular elements with an apex, i.e. vertex, ofthe triangles splitting the incoming fluid flow into desired flow paths.

FIG. 17 provides a perspective view of the top of another alternativecold plate, with the cover removed, and with the rectangular jetsreplaced by pairs of cylindrical jetting orifices.

FIG. 18 provides a cut view of the jetting channels for three jetsshowing fluid flow paths similar to those shown in FIG. 10 but with adifferent, or secondary structural, material covering the jetting impactregions and a tertiary structural material replacing selected portionsof the basic structural material.

FIG. 19 provides a cut view of the jetting walls, jetting channels, andjetting wells for three jets showing fluid flow paths similar to thoseshown in FIG. 10 but with no heat transfer array structural material inthe jet impact region.

FIG. 20 provides a cut view of a jetting location and illustrates howcorners may be rounded, filleted, reconfigured to have smallerstair-stepped features so as to minimize pockets or regions of reducedfluid flow which may enhance heat transfer.

FIG. 21 provides a cut view (sliced in a plane containing the stackingaxis of layers and an axis connecting a side inlet and a side outlet) ofa cold plate according to another embodiment of the invention wherein aheat source to be cooled would be located below the cold plate andwherein the cold plate does not include any baffle elements in the inletregion.

FIGS. 22A-22B provide fluid flow illustrations as derived from an ANSYSFluent simulation.

FIG. 23 provides a cut view of the device of FIGS. 21 to 22B showing aschematic illustration of fluid flow from the inlet through the jets, tothe impact region, through the post jetting channels, to the exitchannel and then to the outlet.

FIG. 24A provides sample dimensions of a jetting orifice in millimeterswhile FIG. 24B provides sample dimensions for features surrounding thejetting orifice which is surrounded by a wall of structural material ofthe jet having leading and trailing surfaces with sharp blade-likeconfigurations.

FIGS. 24C-24D provide perspective sectioned views of a single examplejet and part of a surrounding well wall at two different cut heights soas to further illustrate, the relationship between fin/jet side walls,fin bridging elements, and well side walls.

FIGS. 24E-24F provide a top view and a perspective view, respectively,of a single well region which is cut vertically below the level of thejet side walls so that the entire jetting surface region, bridgingelements, and well walls can be seen.

FIGS. 24G-24H, respectively, provide a perspective view of a singleintegrated jet/fin element (similar to those of FIGS. 24A-24F) from aheat transfer region, that contacts or is in proximity to a heat source,to an inlet portion of the jet as well as a vertically extending cutview through such an integrated jet/fin structure so that at least aportion of the bridge elements can be seen.

FIGS. 24I and 24J provide perspective views of two adjacent integratedjet/fins and wells to illustrate how in at least one embodiment suchelements may be positioned relative to each other.

FIG. 25 provides a cut view of a jetting channel surrounded by a jetwall and fluid return channels along with a height of a solid fin, orwell wall, whose upper surface forms the bottom of the exit channel.

FIG. 26 provides a cut view of the cold plate of FIGS. 21-25 (with inletand outlet headers and the heat transfer array) with sample dimensionsfor the inlet passage (or header) and the exist passage (or header)heights.

FIG. 27 provides a perspective view of another cold plate embodimenthaving an inlet and outlet header structure and a heat transfer arraywhere the two can be independently formed and joined, bonded orotherwise mated at an array bonding surface.

FIG. 28 provides an image of a structure including a single inletproviding manifold distribution of cooling fluid to two heat transferarrays and outlets of the two heat transfer arrays being merged via amanifold into a single outlet.

FIG. 29 provides an image of the temperature/heat profile across the X&Ydimensions of an example semiconductor device while in use.

FIG. 30A provides an outline of an example heat transfer array positionfor cooling a chip of the type having a heat profile as shown in FIG.29.

FIGS. 30B-30C illustrate possible joined (FIG. 30B) and separated (FIG.30C) locations if two heat transfer arrays will be used either withseparate headers or with a single generic or custom manifold.

FIG. 31A provides an image of actual heat transfer array of the type setforth in FIGS. 21-27 as fabricated using Microfabrica's Mica Freeformfabrication process while FIG. 31B provides a close up view of the jetentry ports as seen from the array inlet.

FIG. 32A provides a plot of experimental data obtained from testing adevice like that of FIGS. 31A and 31B.

FIG. 32B provides a plot comparing thermal performance of the device ofFIGS. 31A and 31B against a typical microchannel device wherein theY-axis provides the thermal conductance in W/M²K while the X-axis setforth the flowrate in L/min.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Electrochemical Fabrication in General

FIGS. 1A-1G, 2A-2F, and 3A-3C illustrate various features of one form ofelectrochemical fabrication. Other electrochemical fabricationtechniques are set forth in the '630 patent referenced above, in thevarious previously incorporated publications, in various other patentsand patent applications incorporated herein by reference. Still othersmay be derived from combinations of various approaches described inthese publications, patents, and applications, or are otherwise known orascertainable by those of skill in the art from the teachings set forthherein. All of these techniques may be combined with those of thevarious other embodiments or various aspects of the invention to yieldenhanced embodiments. Still other embodiments may be derived from mixingand matching elements and steps into new combinations based on thevarious embodiments explicitly set forth herein.

FIGS. 4A-4I illustrate side views of various states in an alternativemulti-layer, multi-material electrochemical fabrication process. FIGS.4A-4G illustrate various stages in the formation of a single layer of amulti-layer fabrication process where a second metal is deposited on afirst metal as well as in openings in the first metal so that the firstand second metal form part of the layer. In FIG. 4A a side view of asubstrate 82 having a surface 88 is shown, onto which patternablephotoresist 84 is cast as shown in FIG. 4B. In FIG. 4C, a pattern ofresist is shown that results from the curing, exposing, and developingof the resist. The patterning of the photoresist 84 results in openingsor apertures 92(a)-92(c) extending from a surface 86 of the photoresistthrough the thickness of the photoresist to surface 88 of the substrate82. In FIG. 4D a metal 94 (e.g. nickel) is shown as having beenelectroplated into the openings 92(a)-92(c). In FIG. 4E the photoresisthas been removed (i.e. chemically stripped) from the substrate to exposeregions of the substrate 82 which are not covered with the first metal94. In FIG. 4F a second metal 96 (e.g. silver) is shown as having beenblanket electroplated over the entire exposed portions of the substrate82 (which is conductive) and over the first metal 94 (which is alsoconductive). FIG. 4G depicts the completed first layer of the structurewhich has resulted from the planarization of the first and second metalsdown to a height that exposes the first metal and sets a thickness forthe first layer. In FIG. 4H the result of repeating the process stepsshown in FIGS. 4B-4G several times to form a multi-layer structure isshown where each layer consists of two materials. For most applications,one of these materials is removed as shown in FIG. 4I to yield a desired3-D structure 98 (e.g. component or device).

Various embodiments of various aspects of the invention are directed toformation of three-dimensional structures from materials some, or all,of which may be electrodeposited (as illustrated in FIGS. 1A-4I) orelectrolessly deposited. Some of these structures may be formed from asingle build level formed from one or more deposited materials whileothers are formed from a plurality of build layers each including atleast two materials (e.g. two or more layers, more preferably five ormore layers, and most preferably ten or more layers). In someembodiments, layer thicknesses may be as small as one micron or as largeas fifty microns. In other embodiments, thinner layers may be used whilein other embodiments, thicker layers may be used. In some embodimentsstructures having features positioned with micron level precision andminimum features size on the order of tens of microns are to be formed(i.e. microscale devices). In other embodiments structures with lessprecise feature placement and/or larger minimum features may be formed.In still other embodiments, higher precision and smaller minimum featuresizes may be desirable. In the present application mesoscale andmillimeter-scale have the same meaning and refer to devices that mayhave one or more dimensions extending into the 0.5-30 millimeter range,or somewhat larger and with features positioned with precision in the0.1-10 micron range and with minimum features sizes on the order of1-100 microns.

The various embodiments, alternatives, and techniques disclosed hereinmay form multi-layer structures using a single patterning technique onall layers or using different patterning techniques on different layers.For example, various embodiments of the invention may perform selectivepatterning operations using conformable contact masks and maskingoperations (i.e. operations that use masks which are contacted to butnot adhered to a substrate), proximity masks and masking operations(i.e. operations that use masks that at least partially selectivelyshield a substrate by their proximity to the substrate even if contactis not made), non-conformable masks and masking operations (i.e. masksand operations based on masks whose contact surfaces are notsignificantly conformable), and/or adhered masks and masking operations(masks and operations that use masks that are adhered to a substrateonto which selective deposition or etching is to occur as opposed toonly being contacted to it). Conformable contact masks, proximity masks,and non-conformable contact masks share the property that they arepreformed and brought to, or in proximity to, a surface which is to betreated (i.e. the exposed portions of the surface are to be treated).These masks can generally be removed without damaging the mask or thesurface that received treatment to which they were contacted or locatedin proximity to. Adhered masks are generally formed on the surface to betreated (i.e. the portion of that surface that is to be masked) andbonded to that surface such that they cannot be separated from thatsurface without being completely destroyed or damaged beyond any pointof reuse. Adhered masks may be formed in a number of ways including (1)by application of a photoresist, selective exposure of the photoresist,and then development of the photoresist, (2) selective transfer ofpre-patterned masking material, and/or (3) direct formation of masksfrom computer controlled depositions of material.

Patterning operations may be used in selectively depositing materialand/or may be used in the selective etching of material. Selectivelyetched regions may be selectively filled in or filled in via blanketdeposition, or the like, with a different desired material. In someembodiments, the layer-by-layer build up may involve the simultaneousformation of portions of multiple layers. In some embodiments,depositions made in association with some layer levels may result indepositions to regions associated with other layer levels (i.e. regionsthat lie within the top and bottom boundary levels that define adifferent layer's geometric configuration). Such use of selectiveetching and interlaced material deposition in association with multiplelayers is described in U.S. patent application Ser. No. 10/434,519, bySmalley, now U.S. Pat. No. 7,252,861, and entitled “Methods of andApparatus for Electrochemically Fabricating Structures Via InterlacedLayers or Via Selective Etching and Filling of Voids” which is herebyincorporated herein by reference as if set forth in full.

Temporary substrates on which structures may be formed may be of thesacrificial-type (i.e. destroyed or damaged during separation ofdeposited materials to the extent they cannot be reused),non-sacrificial-type (i.e. not destroyed or excessively damaged, i.e.not damaged to the extent they may not be reused, e.g. with asacrificial or release layer located between the substrate and theinitial layers of a structure that is formed). Non-sacrificialsubstrates may be considered reusable, with little or no rework (e.g.replanarizing one or more selected surfaces or applying a release layer,and the like) though they may or may not be reused for a variety ofreasons.

Definitions

This section of the specification is intended to set forth definitionsfor a number of specific terms that may be useful in describing thesubject matter of the various embodiments of the invention. It isbelieved that the meanings of most if not all of these terms are clearfrom their general use in the specification, but they are set forthhereinafter to remove any ambiguity that may exist. It is intended thatthese definitions be used in understanding the scope and limits of anyclaims that use these specific terms. As far as interpretation of theclaims of this patent disclosure are concerned, it is intended thatthese definitions take presence over any contradictory definitions orallusions found in any materials which are incorporated herein byreference.

“Build” as used herein refers, as a verb, to the process of building adesired structure (or part) or plurality of structures (or parts) from aplurality of applied or deposited materials which are stacked andadhered upon application or deposition or, as a noun, to the physicalstructure (or part) or structures (or parts) formed from such a process.Depending on the context in which the term is used, such physicalstructures may include a desired structure embedded within a sacrificialmaterial or may include only desired physical structures which may beseparated from one another or may require dicing and/or slicing to causeseparation.

“Build axis” or “build orientation” is the axis or orientation that issubstantially perpendicular to substantially planar levels of depositedor applied materials that are used in building up a structure. Theplanar levels of deposited or applied materials may be or may not becompletely planar but are substantially so in that the overall extent oftheir cross-sectional dimensions are significantly greater than theheight of any individual deposit or application of material (e.g. 100,500, 1000, 5000, or more times greater). The planar nature of thedeposited or applied materials may come about from use of a process thatleads to planar deposits or it may result from a planarization process(e.g. a process that includes mechanical abrasion, e.g. lapping, flycutting, grinding, or the like) that is used to remove material regionsof excess height. Unless explicitly noted otherwise, “vertical” as usedherein refers to the build axis or nominal build axis (if the layers arenot stacking with perfect registration) while “horizontal” or “lateral”refers to a direction within the plane of the layers (i.e. the planethat is substantially perpendicular to the build axis).

“Build layer” or “layer of structure” as used herein does not refer to adeposit of a specific material but instead refers to a region of a buildlocated between a lower boundary level and an upper boundary level whichgenerally defines a single cross-section of a structure being formed orstructures which are being formed in parallel. Depending on the detailsof the actual process used to form the structure, build layers aregenerally formed on and adhered to previously formed build layers. Insome processes the boundaries between build layers are defined byplanarization operations which result in successive build layers beingformed on substantially planar upper surfaces of previously formed buildlayers. In some embodiments, the substantially planar upper surface ofthe preceding build layer may be textured to improve adhesion betweenthe layers. In other build processes, openings may exist in or be formedin the upper surface of a previous but only partially formed buildlayers such that the openings in the previous build layers are filledwith materials deposited in association with current build layers whichwill cause interlacing of build layers and material deposits. Suchinterlacing is described in U.S. patent application Ser. No. 10/434,519now U.S. Pat. No. 7,252,861. This referenced application is incorporatedherein by reference as if set forth in full. In most embodiments, abuild layer includes at least one primary structural material and atleast one primary sacrificial material. However, in some embodiments,two or more primary structural materials may be used without a primarysacrificial material (e.g. when one primary structural material is adielectric and the other is a conductive material). In some embodiments,build layers are distinguishable from each other by the source of thedata that is used to yield patterns of the deposits, applications,and/or etchings of material that form the respective build layers. Forexample, data descriptive of a structure to be formed which is derivedfrom data extracted from different vertical levels of a datarepresentation of the structure define different build layers of thestructure. The vertical separation of successive pairs of suchdescriptive data may define the thickness of build layers associatedwith the data. As used herein, at times, “build layer” may be looselyreferred simply as “layer”. In many embodiments, deposition thickness ofprimary structural or sacrificial materials (i.e. the thickness of anyparticular material after it is deposited) is generally greater than thelayer thickness and a net deposit thickness is set via one or moreplanarization processes which may include, for example, mechanicalabrasion (e.g. lapping, fly cutting, polishing, and the like) and/orchemical etching (e.g. using selective or non-selective etchants). Thelower boundary and upper boundary for a build layer may be set anddefined in different ways. From a design point of view, they may be setbased on a desired vertical resolution of the structure (which may varywith height). From a data manipulation point of view, the vertical layerboundaries may be defined as the vertical levels at which datadescriptive of the structure is processed or the layer thickness may bedefined as the height separating successive levels of cross-sectionaldata that dictate how the structure will be formed. From a fabricationpoint of view, depending on the exact fabrication process used, theupper and lower layer boundaries may be defined in a variety ofdifferent ways. For example, they may be defined by planarization levelsor effective planarization levels (e.g. lapping levels, fly cuttinglevels, chemical mechanical polishing levels, mechanical polishinglevels, vertical positions of structural and/or sacrificial materialsafter relatively uniform etch back following a mechanical or chemicalmechanical planarization process). As another example, they may bedefined by levels at which process steps or operations are repeated. Asstill a further example, they may be defined, at least theoretically, aslateral extents of structural material can change to define newcross-sectional features of a structure.

“Layer thickness” is the height along the build axis between a lowerboundary of a build layer and an upper boundary of that build layer.

“Planarization” is a process that tends to remove materials, above adesired plane, in a substantially non-selective manner such that alldeposited materials are brought to a substantially common height ordesired level (e.g. within 20%, 10%, 5%, or even 1% of a desired layerheight or boundary level). For example, lapping removes material in asubstantially non-selective manner though some amount of recession ofone material or another may occur (e.g. copper may recess relative tonickel). Planarization may occur primarily via mechanical means, e.g.lapping, grinding, fly cutting, milling, sanding, abrasive polishing,frictionally induced melting, other machining operations, or the like(i.e. mechanical planarization). Mechanical planarization may befollowed or preceded by thermally induced planarization (e.g. melting)or chemically induced planarization (e.g. etching). Planarization mayoccur primarily via a chemical and/or electrical means (e.g. chemicaletching, electrochemical etching, or the like). Planarization may occurvia a simultaneous combination of mechanical and chemical etching (e.g.chemical mechanical polishing (CMP)).

“Structural material” as used herein refers to a material that remainspart of the structure when put into use.

“Supplemental structural material” as used herein refers to a materialthat forms part of the structure when the structure is put to use but isnot added as part of the build layers but instead is added to aplurality of layers simultaneously (e.g. via one or more coatingoperations that applies the material, selectively or in a blanketfashion, to one or more surfaces of a desired build structure that hasbeen released from a sacrificial material.

“Primary structural material” as used herein is a structural materialthat forms part of a given build layer and which is typically depositedor applied during the formation of that build layer and which makes upmore than 20% of the structural material volume of the given buildlayer. In some embodiments, the primary structural material may be thesame on each of a plurality of build layers or it may be different ondifferent build layers. In some embodiments, a given primary structuralmaterial may be formed from two or more materials by the alloying ordiffusion of two or more materials to form a single material. Thestructural material on a given layer may be a single primary structuralmaterial or may be multiple primary structural materials and may furtherinclude one or more secondary structural materials.

“Secondary structural material” as used herein is a structural materialthat forms part of a given build layer and is typically deposited orapplied during the formation of the given build layer but is not aprimary structural material as it individually accounts for only a smallvolume of the structural material associated with the given layer. Asecondary structural material will account for less than 20% of thevolume of the structural material associated with the given layer. Insome preferred embodiments, each secondary structural material mayaccount for less than 10%, 5%, or even 2% of the volume of thestructural material associated with the given layer. Examples ofsecondary structural materials may include seed layer materials,adhesion layer materials, barrier layer materials (e.g. diffusionbarrier material), and the like. These secondary structural materialsare typically applied to form coatings having thicknesses less than 2microns, 1 micron, 0.5 microns, or even 0.2 microns. The coatings may beapplied in a conformal or directional manner (e.g. via CVD, PVD,electroless deposition, or the like). Such coatings may be applied in ablanket manner or in a selective manner. Such coatings may be applied ina planar manner (e.g. over previously planarized layers of material) astaught in U.S. patent application Ser. No. 10/607,931, now U.S. Pat. No.7,239,219. In other embodiments, such coatings may be applied in anon-planar manner, for example, in openings in and over a patternedmasking material that has been applied to previously planarized layersof material as taught in U.S. patent application Ser. No. 10/841,383,now U.S. Pat. No. 7,195,989. These referenced applications areincorporated herein by reference as if set forth in full herein.

“Functional structural material” as used herein is a structural materialthat would have been removed as a sacrificial material but for itsactual or effective encapsulation by other structural materials.Effective encapsulation refers, for example, to the inability of anetchant to attack the functional structural material due toinaccessibility that results from a very small area of exposure and/ordue to an elongated or tortuous exposure path. For example, large(10,000 μm²) but thin (e.g. less than 0.5 microns) regions ofsacrificial copper sandwiched between deposits of nickel may defineregions of functional structural material depending on ability of arelease etchant to remove the sandwiched copper.

“Sacrificial material” is material that forms part of a build layer butis not a structural material. Sacrificial material on a given buildlayer is separated from structural material on that build layer afterformation of that build layer is completed and more generally is removedfrom a plurality of layers after completion of the formation of theplurality of layers during a “release” process that removes the bulk ofthe sacrificial material or materials. In general, sacrificial materialis located on a build layer during the formation of one, two, or moresubsequent build layers and is thereafter removed in a manner that doesnot lead to a planarized surface. Materials that are applied primarilyfor masking purposes, i.e. to allow subsequent selective deposition oretching of a material, e.g. photoresist that is used in forming a buildlayer but does not form part of the build layer) or that exist as partof a build for less than one or two complete build layer formationcycles are not considered sacrificial materials as the term is usedherein but instead shall be referred as masking materials or astemporary materials. These separation processes are sometimes referredto as a release process and may or may not involve the separation ofstructural material from a build substrate. In many embodiments,sacrificial material within a given build layer is not removed until allbuild layers making up the three-dimensional structure have been formed.Of course sacrificial material may be, and typically is, removed fromabove the upper level of a current build layer during planarizationoperations during the formation of the current build layer. Duringrelease or separation, sacrificial material is typically removed via achemical etching operation but in some embodiments, it may be removedvia a melting operation, electrochemical etching operation, laserablation, or the like. In typical structures, the removal of thesacrificial material (i.e. release of the structural material from thesacrificial material) does not result in planarized surfaces but insteadresults in surfaces that are dictated by the boundaries of structuralmaterials located on each build layer. Sacrificial materials aretypically distinct from structural materials by having differentproperties therefrom (e.g. chemical etchability, hardness, meltingpoint, etc.) but in some cases, as noted previously, what would havebeen a sacrificial material may become a structural material by itsactual or effective encapsulation by other structural materials.Similarly, structural materials may be used to form sacrificialstructures that are separated from a desired structure during a releaseprocess via the sacrificial structures being only attached tosacrificial material or potentially by dissolution of the sacrificialstructures themselves using a process that is insufficient to reachstructural material that is intended to form part of a desiredstructure. It should be understood that in some embodiments, smallamounts of structural material may be removed, after or during releaseof sacrificial material. Such small amounts of structural material mayhave been inadvertently formed due to imperfections in the fabricationprocess or may result from the proper application of the process but mayresult in features that are less than optimal (e.g. layers with stairssteps in regions where smooth sloped surfaces are desired. In such casesthe volume of structural material removed is typically minusculecompared to the amount that is retained and thus such removal is ignoredwhen labeling materials as sacrificial or structural. Sacrificialmaterials are typically removed by a dissolution process, or the like,that destroys the geometric configuration of the sacrificial material asit existed on the build layers. In many embodiments, the sacrificialmaterial is a conductive material such as a metal thought in someembodiments it may be a dielectric material and even a photoresistmaterial. As will be discussed hereafter, masking materials thoughtypically sacrificial in nature are not termed sacrificial materialsherein unless they meet the required definition of sacrificial material.

“Supplemental sacrificial material” as used herein refers to a materialthat does not form part of the structure when the structure is put touse and is not added as part of the build layers but instead is added toa plurality of layers simultaneously (e.g. via one or more coatingoperations that applies the material, selectively or in a blanketfashion, to one or more surfaces of a desired build structure that hasbeen released from an initial sacrificial material. This supplementalsacrificial material will remain in place for a period of time and/orduring the performance of certain post layer formation operations, e.g.to protect the structure that was released from a primary sacrificialmaterial, but will be removed prior to putting the structure to use.

“Primary sacrificial material” as used herein is a sacrificial materialthat is located on a given build layer and which is typically depositedor applied during the formation of that build layer and which makes upmore than 20% of the sacrificial material volume of the given buildlayer. In some embodiments, the primary sacrificial material may be thesame on each of a plurality of build layers or may be different ondifferent build layers. In some embodiments, a given primary sacrificialmaterial may be formed from two or more materials by the alloying ordiffusion of two or more materials to form a single material. Thesacrificial material on a given layer may be a single primarysacrificial material or may be multiple primary sacrificial materialsand may further include one or more secondary sacrificial materials.

“Secondary sacrificial material” as used herein is a sacrificialmaterial that is located on a given build layer and is typicallydeposited or applied during the formation of the build layer but is nota primary sacrificial material as it individually accounts for only asmall volume of the sacrificial material associated with the givenlayer. A secondary sacrificial material will account for less than 20%of the volume of the sacrificial material associated with the givenlayer. In some preferred embodiments, each secondary sacrificialmaterial may account for less than 10%, 5%, or even 2% of the volume ofthe sacrificial material associated with the given layer. Examples ofsecondary sacrificial materials may include seed layer materials,adhesion layer materials, barrier layer materials (e.g. diffusionbarrier material), and the like. These secondary sacrificial materialsare typically applied to form coatings having thicknesses less than 2microns, 1 micron, 0.5 microns, or even 0.2 microns or less. Thecoatings may be applied in a conformal or directional manner (e.g. viaCVD, PVD, electroless deposition, or the like). Such coatings may beapplied in a blanket manner or in a selective manner. Such coatings maybe applied in a planar manner (e.g. over previously planarized layers ofmaterial) as taught in U.S. patent application Ser. No. 10/607,931, nowU.S. Pat. No. 7,239,219. In other embodiments, such coatings may beapplied in a non-planar manner, for example, in openings in and over apatterned masking material that has been applied to previouslyplanarized layers of material as taught in U.S. patent application Ser.No. 10/841,383, now U.S. Pat. No. 7,195,989. These referencedapplications are incorporated herein by reference as if set forth infull herein.

“Adhesion layer”, “seed layer”, “barrier layer”, and the like refer tocoatings of material that are thin in comparison to the layer thicknessand thus generally form secondary structural material portions orsacrificial material portions of some layers. Such coatings may beapplied uniformly over a previously formed build layer, they may beapplied over a portion of a previously formed build layer and overpatterned structural or sacrificial material existing on a current (i.e.partially formed) build layer so that a non-planar seed layer results,or they may be selectively applied to only certain locations on apreviously formed build layer. In the event when such coatings arenon-selectively applied, selected portions may be removed (1) prior todepositing either an additional sacrificial material or structuralmaterial as part of a current layer or (2) prior to beginning formationof the next layer or they may remain in place through the layer build upprocess and then be etched away after formation of a plurality of buildlayers.

“Masking material” is a material that may be used as a tool in theprocess of forming a build layer but does not form part of that buildlayer. Masking material is typically a photopolymer or photoresistmaterial or other material that may be readily patterned. Maskingmaterial is typically a dielectric. Masking material, though typicallysacrificial in nature, is not a sacrificial material as the term is usedherein. Masking material is typically applied to a surface during theformation of a build layer for the purpose of allowing selectivedeposition, etching, or other treatment and is removed either during theprocess of forming that build layer or immediately after the formationof that build layer.

“Multilayer structures” are structures formed from multiple build layersof deposited or applied materials.

“Multilayer three-dimensional (or 3D or 3-D) structures” are MultilayerStructures wherein the structural material portions of at least twolayers are not identical in configuration, not identical in lateralpositioning, or not identical in orientation (i.e. the structuralmaterials on the two layers do not completely overlap one another.

“Complex multilayer three-dimensional (or 3D or 3-D) structures” aremultilayer three-dimensional structures formed from at least threelayers where a line may be defined that hypothetically extendsvertically through at least some portion of the build layers of thestructure and that extends from structural material through sacrificialmaterial and back through structural material or extends fromsacrificial material through structural material and back throughsacrificial material (these might be termed vertically complexmultilayer three-dimensional structures). Alternatively, complexmultilayer three-dimensional structures may be defined as multilayerthree-dimensional structures formed from at least two layers where aline may be defined that hypothetically extends horizontally through atleast some portion of a build layer of the structure that will extendfrom structural material through sacrificial material and back throughstructural material or will extend from sacrificial material throughstructural material and back through sacrificial material (these mightbe termed horizontally complex multilayer three-dimensional structures).Worded another way, in complex multilayer three-dimensional structures,a vertically or horizontally extending hypothetical line will extendfrom one of structural material or void (when the sacrificial materialis removed) to the other of void or structural material and then back tostructural material or void as the line is traversed along at least aportion of its length.

“Moderately complex multilayer three-dimensional (or 3D or 3-D)structures are complex multilayer 3D structures for which thealternating of void and structure or structure and void not only existsalong one of a vertically or horizontally extending line but along linesextending both vertically and horizontally.

“Highly complex multilayer (or 3D or 3-D) structures are complexmultilayer 3D structures for which the structure-to-void-to-structure orvoid-to-structure-to-void alternations occur not only once along theline but also occur a plurality of times along a definable horizontallyor vertically extending line.

“Up-facing feature” is an element dictated by the cross-sectional datafor a given build layer “n” and a next build layer “n+1” that is to beformed from a given material that exists on the build layer “n” but doesnot exist on the immediately succeeding build layer “n+1”. Forconvenience the term “up-facing feature” will apply to such featuresregardless of the build orientation.

“Down-facing feature” is an element dictated by the cross-sectional datafor a given build layer “n” and a preceding build layer “n−1” that is tobe formed from a given material that exists on build layer “n” but doesnot exist on the immediately preceding build layer “n−1”. As withup-facing features, the term “down-facing feature” shall apply to suchfeatures regardless of the actual build orientation.

“Continuing region” is the portion of a given build layer “n” that isdictated by the cross-sectional data for the given build layer “n”, anext build layer “n+1” and a preceding build layer “n−1” that is neitherup-facing nor down-facing for the build layer “n”.

“Minimum feature size” or “MFS” refers to a necessary or desirablespacing between structural material elements on a given layer that areto remain distinct in the final device configuration. If the minimumfeature size is not maintained for structural material elements on agiven layer, the fabrication process may result in structural materialinadvertently bridging what were intended to be two distinct elements(e.g. due to masking material failure or failure to appropriately fillvoids with sacrificial material during formation of the given layer suchthat during formation of a subsequent layer structural materialinadvertently fills the void). More care during fabrication can lead toa reduction in minimum feature size. Alternatively, a willingness toaccept greater losses in productivity (i.e. lower yields) can result ina decrease in the minimum feature size. However, during fabrication fora given set of process parameters, inspection diligence, and yield(successful level of production) a minimum design feature size is set inone way or another. The above described minimum feature size may moreappropriately be termed minimum feature size of gaps or voids (e.g. theMFS for sacrificial material regions when sacrificial material isdeposited first). Conversely a minimum feature size for structurematerial regions (minimum width or length of structural materialelements) may be specified. Depending on the fabrication method andorder of deposition of structural material and sacrificial material, thetwo types of minimum feature sizes may be the same or different. Inpractice, for example, using electrochemical fabrication methods asdescribed herein, the minimum feature size on a given layer may beroughly set to a value that approximates the layer thickness used toform the layer and it may be considered the same for both structural andsacrificial material widths. In some more rigorously implementedprocesses (e.g. with higher examination regiments and tolerance forrework), it may be set to an amount that is 80%, 50%, or even 30% of thelayer thickness. Other values or methods of setting minimum featuresizes may be used. Worded another way, depending on the geometry of astructure, or plurality of structures, being formed, the structure, orstructures, may include elements (e.g. solid regions) which havedimensions smaller than a first minimum feature size and/or havespacings, voids, openings, or gaps (e.g. hollow or empty regions)located between elements, where the spacings are smaller than a secondminimum feature size where the first and second minimum feature sizesmay be the same or different and where the minimum feature sizesrepresent lower limits at which formation of elements and/or spacing canbe reliably formed. Reliable formation refers to the ability toaccurately form or produce a given geometry of an element, or of thespacing between elements, using a given formation process, with aminimum acceptable yield. The minimum acceptable yield may depend on anumber of factors including: (1) number of features present per layer,(2) number of layers, (3) the criticality of the successful formation ofeach feature, (4) the number and severity of other factors affectingoverall yield, and (5) the desired or required overall yield for thestructures or devices themselves. In some circumstances, the minimumsize may be determined by a yield requirement per feature which is aslow as 70%, 60%, or even 50%. While in other circumstances the yieldrequirement per feature may be as high as 90%, 95%, 99%, or even higher.In some circumstances (e.g. in producing a filter element) the failureto produce a certain number of desired features (e.g. 20-40% failure maybe acceptable while in an electrostatic actuator the failure to producea single small space between two moveable electrodes may result infailure of the entire device. The MFS, for example, may be defined asthe minimum width of a narrow processing element (e.g. photoresistelement or sacrificial material element) or structural element (e.g.structural material element) that may be reliably formed (e.g. 90-99.9times out of 100) which is either independent of any wider structures orhas a substantial independent length (e.g. 200-1000 microns) beforeconnecting to a wider region.

Thermal Control and Heat Transfer Arrays, Cold Plates, Systems, andMethods

In various embodiments of the invention, heat transfer arrays may beformed using the multi-layer, multi-material electrochemical methods,and other methods, set forth herein with any desired orientationrelative to a stacking axis of the layers that form the device. However,in some embodiments it is preferred that the formation orientation besuch that the bottom part or bottom surface of the heat transfer array(i.e. the part in contact with or in closest proximity to thesemiconductor device or devices to be cooled) be formed parallel to theplane of the layers that are being stacked. In some embodiment, it ispreferred that the primary jetting direction of fluid from the jettingstructures be substantially perpendicular to the planes of the layers(i.e. substantially parallel to the stacking axis, i.e. preferablewithin 20 degrees of the stacking axis, more preferably within 10degrees of the stacking axis, and even more preferable within 5 degreesof the stacking axis). In some embodiments, the jets may have jettingdirections that are intentionally not parallel to the stacking access.In some embodiments, the heat transfer arrays may not have bottoms or atleast may not have contiguous bottoms but instead the base of the arraymay be a semiconductor device (e.g. the back side of the wafer on whichthe active components are formed or a protective layer formed on thewafer material) or other heat source. In some embodiments, the heattransfer array may have a rectangular configuration while in otherembodiments it may have a different configuration, e.g. a configurationthat matches a shape and a size of a semiconductor chip or hot spot onthe chip that is to undergo thermal management. In some embodiments, anindividual heat transfer array may be formed as a single monolithicdevice while in other embodiments, heat transfer arrays may be formed asmultiple elements that are bonded or otherwise joined one to anotherafter formation. In some embodiment, multiple heat transfer arrays maybe held apart from one another and even used in conjunction withmultiple semiconductor devices. In some embodiments heat transfer arraysmay be formed with etching holes that allow removal of a sacrificialmaterial after all layers have been formed or after formation of only aportion of the layers. Such etching holes may be filled in or sealedafter the layer formation process or after etching but during the layerformation process. In other embodiments, a top or lid and/or base orbottom may be formed separately to allow efficient removal ofsacrificial material. Other embodiments may not require special openingsto remove sacrificial material. Various methods exist to handlesacrificial material removal and/or multi-component device assembly asare set forth in some of the patents and patent applicationsincorporated herein by reference.

FIG. 5 provides a schematic view of a thermal management system (e.g. acooling system) that includes a thermal management device in the form ofa cold plate that includes at least one thermal transfer array and inletand outlet headers or manifolds. The system further includes a heatexchanger, a pump and a thermal interface material for effectivelycoupling the thermal management device to a heat source (e.g. asemiconductor chip or group of chips). In this example system, thermalinterface materials include thermal grease, solder, a thermal pad, or nomaterial at all. The fluid pump may take a variety of forms including,for example, a centrifugal pump, a membrane pump, a piston pump, or arotary pump. In this example, the heat exchanger may take anyconventional form such as a finned array with a fan, a radiator, athermal electric device, a liquid to liquid heat exchanger, aliquid-to-air heat exchanger, an evaporative cooler, and the like. Theheat transfer array may take a number of different forms including amicrojet array, a microchannel array, a hybrid microjet microchannelarray, an integrated fin microjet array, a microchannel and integratedfin and microjet array. As used herein, an integrated fin and microjetarray refers to the jetting paths and orifices extending through thefins and the fins providing opening near their distal ends to allowjetting to occur while still having intimate contact between the finsand the heat transfer surface or surfaces. Fluid pipe of flow pathsbetween components may take any of a variety of forms including forexample copper pipes, flexible plastic pipes, relatively large channelsin solid blocks of material, and the like.

FIG. 6 provides a schematic view of an alternative thermal managementsystem (e.g. a cooling system) that includes a thermal management device(e.g. a cold plate that includes a heat transfer array in combinationwith separately formed inlet and outlet headers or manifolds). As withthe embodiment of FIG. 5, the system includes a heat exchanger. But inthis embodiment, the system includes a pump that is joined to or is partof the thermal management device (e.g. a pump directly on top of thedevice with an impeller that drives liquid into and/or pulls liquid outof the heat transfer array). In this embodiment, as well as in that ofFIG. 5, the thermal management device is effectively coupled to a heatsource via a thermal interface material. In some variations, inclusionof a separate thermal interface material may not be necessary (forexample, when a surface of the heat source acts a jetting impingementsurface).

FIG. 7 provides a perspective view of an example cold plate with itscover removed that includes an integrated microchannel and microjetarray (heat transfer array) wherein the heat source (not shown) is to bepositioned below the array and wherein cooling fluid (e.g. water) flowsinto an inlet 702 from the left side of the device over the baffle plateand then into the slot jets 704 to extract heat from the source and thenfinally flows out through the outlet 706 on the right side of thedevice. In this embodiment the baffle plate includes a plurality ofcylindrical flow redirection elements (fin array) 708 that provide anenhanced fluid flow pattern before the fluid enter the jettingstructures.

FIG. 8 provides a cut perspective view of the cold plate with anintegrated heat transfer array and inlet/outlet system such that theinlet, the baffle plate, baffle elements, jets, and post jetting flowchannels and outlet can be seen. In this example, the inlet includesinlet orifice, a relative large spreading region adjacent thereto andthe baffle plate flow region, while the outlet includes the outletorifice and the relatively large collecting region adjacent there to,while the heat transfer array portion of the device includes the jets,the jetting wells, and the after jetting flow paths (and associatedstructures) that travel around the sides of the jets as fluid movetoward the outlet. In some variations of this embodiment, the heattransfer array portion of the cold plate may be fabricated using amulti-layer multi-material electrodeposition method while the otherparts of the cold plate may be fabricated via other methods (e.g.machining via water, laser, physical cutting tools, abrasive cuttingtools, etching, or the like) and thereafter mating via bonding orclamping made to occur in combination with appropriate sealants. Inother variations the whole device may be made monolithically viamulti-layer multi-material electrodeposition method using a single metalor plurality of different metals and possibly other materials.

Arrows in FIG. 8 show fluid flow 810 through the inlet, flow 815 pastthe structures on the baffle plate, flow 820-1 to 820-4 through thejets, flow 825 along the base of the array (in the jetting wells) at thepoint of closest contact with the heat source, flow 830 from the jettingwell out of the local jetting channels, flow 835 through the postjetting channel, and flow 840 out of the outlet. In some alternativeembodiments, the transfer array may not have a solid bottom, or base,but instead fluid may be directed directly onto the upper surface of theheat source (e.g. silicon or other semiconductor surface), in stillother embodiments, the base may take the form of a series of separateimpact plates that are located above the heat source surface in theregion where direct perpendicular impact will occur but are non-existentwhere largely horizontal or tangential fluid flow over the heat sourcewould occur.

In some embodiments, the array of FIG. 8 may be formed from a pluralityof layers built up using a multi-layer, multi-material electrochemicalfabrication process as described above wherein a direction of layerstacking may be parallel to a direction of jetting. In otherembodiments, layer stacking directions may be different.

In some preferred embodiments, though not necessarily all embodiments,the jetting structures also act as fins, or worded another way, some ofthe fin structures have embedded jets. In the depicted embodiments, thejetting impact surfaces are closer to a heat source surface (e.g. asemiconductor surface) than is the primary exit path, channel, or level.These jetting surfaces may be considered to be located that the bottomof jetting wells with each jet having its own well and with the fluidexit path being above the floor of the jetting wells. In someembodiments, it is possible to have multiple jets (e.g. 2, 3 or 4 jets)share a jetting well while still having the primary fluid exit pathbeing above the floor of the jetting wells. In some embodiments, thelower surface of the jet side walls (excluding bridging material thatprovides fin functionality) is located below (i.e. closer to the floorof the jetting wells than is the primary fluid exit channel) while inother embodiments, the lower extent of the jet side walls may be locatedabove a primary fluid exit channel.

In some embodiments jetting may occur directly on a heat source surface(e.g. a silicon or other surface of the semiconductor that is beingcooled) while other embodiments may jet onto a floor of the transferarray which has been bonded to the semiconductor surface or to anindependent jetting surface that has been transferred to thesemiconductor surface or deposited directly thereon. Such an independentjetting surface may be located only in jetting well regions, in portionsof jetting wells where substantially perpendicular impact of jettedfluid is to occur (e.g. within 15 degrees of perpendicular, within 10degrees, within 5 degrees, or even within 1 or 2 degrees) or may belocated as a complete coating applied to the semiconductor surface. Insome embodiments the semiconductor surface may be the back side of asemiconductor (i.e. the side opposite to where semiconductor deviceformation occurs). In some embodiments, the semiconductor surface mayundergo etching or planarization to reduce its thickness prior tolocating, applying or forming the transfer array (i.e. the microchannel,microjet array) thereon. In some embodiments the reduction in thicknessmay be uniform while in other embodiments the reduction in thickness maybe non-uniform and may actually be used to form flow channels or jettingwells that may be used by the transfer array. In some embodiments,thinning may be followed by deposition of one or more materials toprovide enhanced surface properties. In some embodiments, for examplesemiconductor thickness may start in the range of 500-700 microns (ums)and be thinned to 400 microns, 300 microns or even less. In someembodiments, mounting the transfer array onto the semiconductor mayoccur by direct bonding, clamping the devices together with anintermediate thermal transfer material (e.g. solid or flowable) that mayprovide some thermal expansion stress relief. In still otherembodiments, bonding or attachment to a semiconductor may not occur butinstead the cooling device may be bonded or attached to another part ofa semiconductor package such as a PCB, a PWB, or an integrated heatspreader (IHS) to which the semiconductor device is attached. Someembodiments that make use of an intermediate thermal grease may target athickness of between 25-50 microns while bonding that occurs via soldermay target solder thicknesses in the range of 25-75 microns. Someembodiments may use o-ring seals, solder, or other sealants whenbringing separately formed elements into hermetic configuration. Someembodiments may make use of ultrasonic or diffusion bonding to ensureproper sealing.

FIG. 9 provides a perspective view of a device similar to that of FIGS.7-8 where a portion of the baffle plate 901 is shown along with fluidflow lines 915-1 to 915-3 showing some possible fluid flow paths throughan inlet layer or region around the baffle elements 904 as the fluidprogresses toward individual jet orifices 918. The baffle elements maytake on a variety of different forms to aid in efficiently channelingthe fluid flow.

FIG. 10 provides a cut side view of several of the jet elements havingwalls 1021 and orifices 1018 similar to the devices of FIGS. 7-9 suchthat the inside channel (i.e. orifice or nozzle) 1018 of the jet, theflow path through jetting channel 1020 and the fluid impact region 1026below the jets are visible with the post jetting fluid initiallyfollowing flow paths 1025-A and 1025-B. The fluid inlet channel 1014 canbe seen above the jet orifice entry level where the fluid flow 815 ofFIG. 8 would exist as the fluid flow past baffle elements 1004-I, thefluid exit channel 1034 can also be seen with arrows 1035A and 1035Bshowing examples of where the fluid flow 835 of FIG. 8 would exist as itflow past baffles or solid fins 1004-0. Fluid flows of the jettingchannel 1020 and of microchannel 1030 are anti-parallel andsubstantially perpendicular to a plane of the surface on to whichjetting occurs though some relatively small component of flow may beparallel to the surface that receives jetted material. Conversely fluidflows 1025-A and 1025-B and 1035-A and 1035-B are substantially parallelto the surface on to which jetting occurs though some relative smallcomponent of flow may be perpendicular to the surface that receivesjetted material. FIG. 10 also shows that the fluid flow 1035-A throughthe exit layer, or region, is spaced between the inlet layer, or region,and the top of fluid wells into which jetting occurs. The bottom of thejet walls are spaced vertically between the surface onto which jettingoccurs and a level of the top of the wells (which forms the lowerboundary of the exit layer) such that jetted material after impingementmust flow horizontally or laterally 1025 a small distance prior tochanging to a vertical flow direction of microchannel 1030 between thejet walls and the well walls before again turning back to a horizontal,or lateral, flow direction 1035 in the exit layer. The primary heattransfer region is considered to be the region at the bottom of thejetting wells though heat is extracted by the flowing liquid as it movespast the well walls, over the tops of the wells and around the bafflesor fins in region 1034. In some embodiments as can be seen in FIG. 21 aportion, or portions of the jet side walls may extend down and contact,bond to, or be formed integral with the surface of jetting fluidimpingement thus making jetting structures in such embodiments alsofunction as heat flow fins from which pre-jetted liquid and post jettedliquid can absorb heat to further enhance heat transfer.

FIG. 11 provides a cut view of a single microjet region of a devicealong with some sample dimensional ranges that might be used in someembodiments. Of course in other embodiments, the dimensions may varyaway from the ranges indicated herein.

FIG. 12 provides a cut top view of the baffle plate along with somesample dimensions for the jet, baffles, and spacing between baffleelements. In some embodiments jet dimensions, baffle size andconfiguration, and baffle spacing as well as spacing between jets mayvary depending on where these structures are located relative to theinlet, sidewalls, back wall, or the like.

In some embodiments jets may change dimensions vertically along the flowpath (e.g. by widening or narrowing at desired locations). In someembodiments small corner regions may be filled in to minimize locationswhere fluid stagnation or low flow may exist so as to further enhanceheat transfer. Such regions may exist in the inlet layer, the exitlayer, or even the regions where well floors and well walls meet. Inother embodiments, surface texturing may be added to key heat transferregions to further enhance surface area contact and thus heat transfer

FIG. 13 provides another perspective cut view of a single jet regionwhere the post jetting flow regions along the well walls include solidfin elements and channels to provide additional surface area foroptimizing heat transfer.

FIG. 14 provides a chart illustrating the anticipated performanceenhancement that may be achievable by some embodiments of the presentinvention where microchannels or optimized microchannels and microjetarrays are combined for improved thermal conductance, decreased pressuredrop across the heat transfer array, and improved heat flux through theheat transfer array.

FIG. 15 provides a perspective view of the top of an alternative coldplate (i.e. heat transfer array and inlet/outlet combination) with thecover in place and with the inlet moved from the left side to the topand with the single outlet of FIG. 7 modified into two outlets with oneon the left and one on the right. In other alternatives, the positionsof the outlet(s) and inlet(s) may be reversed or the numbers of themchanged.

FIG. 16 provides a perspective view of the top of another alternativecold plate, with the cover removed, and with the cylindrical baffleelements replaced by triangular elements with an apex, i.e. vertex, ofthe triangles splitting the incoming fluid flow into desired flow paths.In other embodiments, other baffle configurations are possible and mayinclude wing shaped elements, diamonds, rectangles, ovals, or the like.In still other embodiments, the baffle elements may be located behindjet openings as opposed to in front of them. In still other embodiments,more than one type of baffle element may be employed wherein the typeused may be dependent on the location of the baffle relative to thejetting orifices. In some alternative embodiments, baffle elements maynot only include varying configurations in the plane of layer formationbut also in the stacking direction of layer formation (e.g. a bafflebehind a jet orifice may include a vertically curved or stair steppedstructure that helps redirect horizontal fluid flow into vertical fluidflow over a jetting orifice. In some alternative embodiments, a backplate may have a curved shape that redirects fluid flow smoothly back toa front side of the cold plate so that it may make another flow passpast the orifices as opposed to forming pockets of low flow or stagnatedfluid. In still other embodiments, the inlet layer may have a reducedbaffle/fin count or even be baffle/fin free so as to provide the overallcold plate with a reduced pressure drop.

FIG. 17 provides a perspective view of the top of another alternativecold plate, with the cover removed, and with the rectangular jetsreplaced by pairs of cylindrical jetting orifices. In other embodiments,other orifice configurations are possible as well as openingconfigurations that allow flow of fluid from the jetting cavity or wellback to the exit channel (to be discussed hereinafter).

FIG. 18 provides a cut view of the jetting channels for three jetsshowing fluid flow paths similar to those shown in FIG. 10, however inthe embodiment of FIG. 18 two changes have been made, (1) the materialcovering the jetting impact regions has been changed from a first, orbasic, structural material (e.g. nickel, a nickel alloy, palladium, orthe like) to different, or secondary structural, material 1802 and (2)selected portions of the basic structural material have been replacedwith a tertiary structural material 1804. The secondary structuralmaterial may be a harder material such as, for example, rhodium as setforth in the figure, so as to limit any wear or erosion that mightotherwise result from the concentrated fluid impingement. The tertiarymaterial may be a material of higher conductivity (e.g. copper, silver,or gold) than the basic structural material (e.g. nickel, a nickelalloy, palladium, or the like) but may be lacking in some otherimportant property (e.g. hardness, durability, strength, incompatibilitywith an etchant that may be used to remove a sacrificial material, orthe like). In some embodiments, the tertiary material and thesacrificial material may be the same material and thus the tertiarymaterial may require protection by a shell of the basic structuralmaterial to keep it from being removed during sacrificial materialetching. In some embodiments the secondary material and/or tertiarymaterial may be added to the primary build material in any mannerdesired (e.g. performed plugs that are inserted into position as layerare formed or after layer formation if access is available, depositsthat are made after layer formation is completed, deposits made duringan interpretation to the layer formation process, or deposits made aspart of a multi-layer, multi-material formation process). In someembodiments, the roles of the secondary and tertiary material may befilled by the same material. In some embodiments, only a basicstructural material and a secondary material may be used (i.e. notertiary material) while in other embodiments the basic material may beused with just the tertiary material (i.e. no secondary material), whilein still other embodiments one or more additional specialized materialsmay be added for various purposes either alone or in combination withother materials.

FIG. 19 provides a cut view of the jetting walls, jetting channels, andjetting wells for three jets showing fluid flow paths similar to thoseshown in FIG. 10, however the embodiment of FIG. 19 indicates that thereis no heat transfer array structural material in the jet impact regionthus allowing the jetted fluid to impact directly on to the material ofthe heat source. In such situations, as well as in embodiments where aheat transfer array base exists, the heat transfer array and the heatsource 1902 may be bonded or sealed 1904 to one another in anyappropriate manner (e.g. soldering, conductive epoxy, pressure fittingwith a softer highly conductive metal, clamping with o-ring seals,ultrasonic bonding, diffusion bonding, brazing, or the like). In otherembodiments, the heat transfer array may carry with it an impact surfaceof a desired size, shape and material that can be bonded or seatedagainst the heat source while still providing at least a portion of thesurrounding area as a direct fluid impact zone. In other embodiments, animpact pad of a desired material may be formed on or attached to theheat source prior to mounting the heat transfer array.

FIG. 20 provides a cut view of a jetting location and illustrates howcorners 2002, 2004, and 2006 may be rounded, filleted, reconfigured tohave smaller stair-stepped features, which may be provided by techniquesset forth in U.S. Pat. No. 7,198,704, so as to minimize pockets orregions of reduced fluid flow which may enhance heat transfer.

FIG. 21 provides a cut view (sliced in a vertical plane defined by thestacking axis of the layers of the device and an axis connecting a sideinlet and a side outlet) of a cold plate according to another embodimentof the invention showing (1) an inlet region 2102 which may beconsidered part of a header or manifold, (2) an outlet region 2104 whichmay, at least in part be considered part of a header or manifold, (3) acap above the inlet and the outlet regions defining a top of a header ormanifold, (4) a lateral dividing wall between the inlet and outletregions, (5) a horizontal jet inlet surface 2108 defining a bottom of aheader or manifold on the inlet side and including a plurality of jetchannel entrance ports 2106, (6) a heat exchange base 2110 having a corematerial 2112 encased in a shell material 2114 and providing a pluralityof individual jetting surfaces and primary heat transfer regions withinjetting wells, (7) a plurality of microjets extending from the jet inletsurface to a position spaced from floors of the jetting wells andincluding spaced apart extensions or bridging element that contact theimpingement surface (or merging with it) of the heat exchange basewithin each jetting well to provide heat conduction fin functionality,(8) post-jetting fluid channels located between the side walls of thejets and the well walls and an exit region above the jetting wells whereexiting fluid can move laterally flow between the inlet region and theupper surfaces of the wells past jet sidewalls and any additional solidfins or baffles. In many respects the device is similar to those of theprior figures but some differences exist. The device of this embodimentdoes not include any baffle elements in the inlet region, it includesoblong smooth surfaced jets having elongated cross-sectional dimensionsparallel to the axis extending from the inlet to the outlet, a stairstepped structure 2118 connecting the cap and a right most inlet chamberwall (i.e. a sloping down structure on the back wall of the inletchamber), a stair stepped lower surface 2120 and stair stepped uppersurface 2122 of an outlet (i.e. a sloping surface that may help directfluid out of the heat transfer array while reducing stagnate or slowflowing fluid traps.

FIGS. 22A and 22B provide fluid flow illustrations as derived from anANSYS Fluent simulation. FIG. 22B provides a close up of the fluid flowmovements in the region of the microjets while FIG. 22A provides a viewof the entire flow from inlet to outlet. The colors in these imagesrelate to the flow speed of the heat transfer fluid with bluerepresenting the lowest flow rate and yellow and red the highest flowrate.

FIG. 23 provides a cut view of the device of FIGS. 21 to 22B showing aschematic illustration of fluid flow from the inlet through the jets, tothe impact region, through the post jetting channels, to the exitchannel and then to the outlet. The coloring of the fluid flow lineindicates how the liquid (e.g. water) is heating up as it flows fromleft to right where blue represents cool liquid and yellow, orange, andbrown represents warmer liquid.

FIG. 24A provides sample dimensions of a jetting orifice in millimeterswhile FIG. 24B provides sample dimensions for features surrounding thejetting orifice 2418 (e.g. jet side walls, bridging elements thatconnect the lower portion of the jet to well side walls, channels formoving fluid from the jetting region along the jet side walls and wellside walls to a primary exit channel located above the jetting well).The jet orifice is surrounded by a wall of structural material 2419forming the jet side walls wherein the jet side walls, in this example,provide leading and trailing surfaces with sharp blade-likeconfigurations. As the jet side walls enter a jetting well, the jet sidewalls, in this example, are spaced from well side walls by four gaps orchannels 2428-A to 2428-D that define vertically extending post-jettingchannels that feed the heat transfer fluid (e.g. water) from the impactarea or floor of the jetting well to a primary exit channel. The fourpost-jetting channels are in turn spaced from one another by fourregions of structural material or solid conductive material bridges thatconnect the jet side wall material 2419 to well side wall material 2431.These bridges provide a direct metal conductive path between the heatsource and the jet side walls thus providing the jetting structures withdirect heat conductive fin functionality. In such embodiments, thebridges may extend a portion of the jet side walls completely to the jetimpact floor while in other embodiments, the bridges may make a solidconductive connection between the jet sidewalls and the floor via thewell side walls or via a somewhat laterally offset path (i.e. a pathbetween a theoretical vertical jet side wall that extended completely tothe floor and a theoretical vertical well wall that extended to thefloor in absence of the bridge material). In such embodiments, thejetting structure may be said to have fin functionality oralternatively, these fin structures may be said to have embedded jets orjet functionality. Such systems may be thought of as having a higherlevel of integration than those systems that have jets that do notprovide fin functionality or those systems that have fins but withoutjetting functionality.

FIGS. 24C and 24D provide perspective sectioned views of a singleexample jet and part of a surrounding well wall at two different cutheights so as to further illustrate, the relationship between fin/jetside walls, fin bridging elements, and well side walls. As shown in FIG.24C bridging elements 2430-AD and 2430-AC can be seen (only 2430-AD islabeled) at the lower end of the jet wall material 2419 and between thejet wall material 2419 and the well sidewall material 2431. In practice,these three differently labeled elements may range from physicallydistinct materials or they may all be made from a single commonmaterial. This bridging material provides a solid conductive directbridge from the jet wall to the jetting floor near the central region ofthe jetting floor 2420-C or the side region of the jetting floor 2420-Sand semi-directly from the jet wall to the jetting floor near sideregion 2420-S via the well side walls. FIG. 24D provides a perspectivesectioned view with an extended portion of the jet side wall material2419 shown extending above an upper surface 2432 of the well side wallmaterial into a primary exit channel region. FIG. 24D also labelsadditional bridging elements and post jetting channels with labelssimilar to those used in FIG. 24B.

FIGS. 24E and 24F provide a top view and a perspective view,respectively, of a single well region which is cut vertically below thelevel of the jet side walls so that the entire jetting surface region;bridging elements 2430-AD, 2430-AB, 2430-BC, and 2430-BD; and well wallscan be seen.

FIGS. 24G and 24H, respectively, provide a perspective view of a singleintegrated jet/fin element (similar to those of FIGS. 24A-24F) from aheat transfer region, that contacts or is in proximity to a heat source,to an inlet portion of the jet as well as a vertically extending cutview through such an integrated jet/fin structure so that at least aportion of the bridge elements can be seen. FIG. 24H also shows regions2440 which represent volumes of solid conductive material that may beformed of a different material than that which forms the surface of thefloor 2420. In embodiments where different materials may be used, floormaterial may be selected based on a desire to optimize durability of thefloor material and thermal conductivity (e.g. Ni—Co, Pd, or Rh) or whilefiller material 2440 may be selected with a larger emphasis on thermalconductivity (e.g. Cu) to improve overall heat transfer.

FIGS. 24I and 24J are similar to FIGS. 24G and 24H with the exceptionthat instead of showing views of a single integrated jet/fin and well,they show two adjacent integrated jet/fins and wells to illustrate howin at least one embodiment such elements may be positioned relative toeach other.

In other embodiments, variations of the configurations shown in FIG.24A-24J may exist. Such variations may include different dimensionalconfigurations, different configurations of bridging elements, bridgingelement patterning not extending the entire length of the outer surfacesof a jet element, different numbers of bridging elements and post jetchannels existing per jet, different orientations of elements, differentspacing or positions for adjacent jets, different patterns forincorporating different materials, and the like.

FIG. 25 provides a cut view of a jetting channel 2418 surrounded by thejet wall 2419 and fluid return channels 2428-C and 2428-D along with aheight 2502, 0.080 mm to 0.300 mm, of a solid fin 2529, or well wall,whose upper surface forms the bottom of the exit channel. An exampledimensional range for height 2502 is also given. A height 2504, 0.030 mmto 0.100 mm, of the impact region or jetting floor is also shown with anexample range of dimensions. In other embodiments other dimensionalranges may be possible.

FIG. 26 provides a cut view of the cold plate of FIGS. 21-25 (with inletand outlet headers and the heat transfer array) with sample dimensionsfor the inlet passage (or header) and the exist passage (or header)heights. In some embodiments the dimensions of inlet header height 2602,0.3 mm or more, and exit manifold height 2604, 0.3 mm or more, are setto be at least 3× the hydraulic diameter of the jet as defined by theinner contour of the jet of FIG. 24A. Hydraulic diameter is defined bythe definition Dh=4*A/P, where A=cross section area of flow channel,P=perimeter length of flow channel. In embodiments where the header ormanifold has a large enough flow path, a reduced need for differentialtailoring of jet dimensions and jet spacing may exist to get uniformheat removal. Such differential treatment may still be required based onsemiconductor hot spot location or level of hot spot heat generation. Insome embodiments outlet location may be varied from the right sideconfiguration depicted in the present embodiment based on the particularheat removal requirements of particular application. For example, theoutlet may surround the inlet, multiple smaller outlets ay be used incombination with a single inlet, or a single outlet may be used incombination with multiple inlets.

FIG. 27 provides a perspective view of another cold plate embodimenthaving an inlet and outlet header structure 2702 with walls 2718, afluid inlet 2714, and a fluid outlet 2716 and a heat transfer array 2704where the two can be independently formed and joined, bonded orotherwise mated at an array bonding surface 2708. The inlet chamber 2710and outlet chamber 2712 of the header and/or the array may include a lip2706 near a bonding material location such that the lip can help ensurethat any bonding material (e.g. solder) does not enter the chambers. Insome embodiments one or both bonding surfaces of the array and headermay be coated with a bonding material (e.g. solder, such as AuSneutectic or SnAg eutectic, high temperature epoxy, or the like) prior tobeing brought into contact. Upon contact or upon other activation (e.g.heating, ultrasonic vibration, pressure, light exposure (e.g. if theheader is transparent or the like)) bonding may be made to occur. Inother embodiments, bonding may occur without use of an intermediatebonding agent such as by laser welding, ultrasonic bonding, diffusionbonding, o-ring sealing with clamping, or like). In some embodimentsselected portions of surfaces of one or both the header and the arraymay be treated (e.g. roughened, smoothed, chemically activated, appliedwith surface coatings, or the like) to enhance bonding or wetting of thesurface or surfaces in certain locations. In other embodiments suchtreatments may be used to discourage bonding or flow of a bondingmaterial. For example the lip area may be configured, conditioned,coated, or otherwise treated to reduce flow of bonding material so as tokeep bonding material from entering the channels. As another example,selected portions of a surface of a heat transfer array that is formedfrom a material that is not particularly friendly to solder wetting(e.g. NiCo, TiW) may receive a coating of a more wettable material (e.g.Pd) onto which solder may be placed and bonding may occur while otherportions of the micro-array (e.g. the lip or area around the lip mayforego such coating).

In some embodiments, not shown, instead of a single elevated lip aroundthe channel openings of the micro array, multiple concentric lips, orlips of other configurations may be may formed on the micro-arraysurface and possibly one or more corresponding notches formed in thebonding surface of the header or manifold such that upon mounting andflowing of a bonding agent some overlap or interlacing of surfacefeatures occurs. In some embodiments the micro-array may be made to haverecesses while the header may be made to have or more protrusions. Insome embodiments, the regions between all successive lips may be filledwith bonding or sealing material, while in other embodiments onlyregions between a portion of the lips may receive bonding or sealingmaterial. In some embodiments the header may be formed in any of avariety of ways (e.g. by molding or by CNC machining) from aluminum,copper or any other suitable material. The heat transfer array orportions of the array may also be formed in a number of differentmanners such as by electrochemical multi-material, multi-layer methodsas set forth herein. The array may be formed from a plurality ofmulti-material layers (including one or more structural materials oneach layer and one or more sacrificial materials on each layer where thestructural or sacrificial materials may be different on differentlayers. Structural materials may include, for example, nickel cobalt forstrength, rhodium for wear resistance, copper for enhanced heat flow,palladium for strength or enhanced wettability, TiW or epoxy or othermaterial for use as a solder mask, a solder flux, or other bondingmaterial or bonding promoter deposited as part of the layer formationprocess. Seed layers and dielectric materials (e.g. plastics orceramics) may also be incorporated into the formation process asdesired.

FIG. 28 provides an image of a structure including a single inlet 2802providing manifold distribution of cooling fluid to two heat transferarrays 2804-A and 2804-B and outlets of the two heat transfer arraysbeing merged via a manifold into a single outlet 2806.

FIG. 29 provides an image of the temperature/heat profile across the X&Ydimensions of an example semiconductor device while in use, showingrelatively cool areas 2902 and hot spots 2904-A, 2904-B, and 2904-Cwhere heat transfer arrays might be most useful. As shown, the device isnot uniformly heated but has a heterogeneous temperature profile. Heatdistribution across the device may be improved by use of a conductiveheat spreader but heat removal from certain areas of the device may bebetter handled by use of one or more heat transfer arrays of as setforth herein. Of course if the heat transfer array is the same size asthe semiconductor chip or larger it may simply cover the whole chip;however, if a single microjet array is smaller than the chip thenselective location of the heat transfer array or use of multiple arraysmay be most beneficial.

FIG. 30A provides an outline of an example heat transfer array position3002 for cooling a chip of the type having a heat profile as shown inFIG. 29. FIGS. 30B and 30C illustrate possible joined heat transferarrays at locations 3006-A and 3006-B (FIG. 30B) and separated heattransfer arrays at locations 3008-A and 3008-B (FIG. 30C). The two heattransfer arrays may be used either with separate headers or with asingle generic or custom manifold. In other embodiments, differentnumbers of heat transfer arrays, heat transfer array configurations,header numbers and configurations, and manifold numbers andconfigurations can be used as appropriate to get the temperature profileof device to be held in an acceptable temperature range.

FIG. 31A provides an image of actual heat transfer array of the type setforth in FIGS. 21-27 as fabricated using Microfabrica's Mica Freeformfabrication process while FIG. 31B depicts a close up view of the jetentry ports as seen from the array inlet.

FIG. 32A depicts a plot of experimental data obtained from testing adevice like that of FIGS. 31A and 31B. This plot depicts (1) the thermalconductance of the heat transfer array in W/M²K versus water flow rate(L/min) via the top line (with triangles) and pressure drop (PSI) versusflowrate (L/min) via the lower line (with diamonds). In theseexperiments the surface temperature of the semiconductor device was heldat 65° C. with a water inlet temperature of 20° C. FIG. 32B provides aplot comparing thermal performance of the device of FIGS. 31A and 31Bagainst a typical microchannel device wherein the Y-axis provides thethermal conductance in W/M²K while the X-axis set forth the flowrate inL/min. The plot indicates that the testing of a device shown in FIGS.31A and 31B yielded a 6× improvement (line with triangles) in thermalconductance compared to a typical microchannel device at 0.5 liters perminute (LPM) with less than a 50% increase in pumping power compared toa typical microchannel device (line with diamonds).

In some embodiments, devices (e.g. microjet and microchannel portions ofthe cold plate, i.e. the heat transfer array portion) may be fabricatedby an additive layer process such as a multi-layer, multi-materialprocess as set forth herein. Such devices may undergo post processingtreatment or undergo one or more breaks in the middle of layerprocessing to modify the structural or surface configuration of thestructures being formed or to apply additional processing steps thatmight not be effectively implementable after layer formation is complete(e.g. use of a high pressure abrasive particle flow to smooth sharpcorners in fluid channels, application of coatings or surface treatmentswhile access to such surfaces is not blocked by material formingsubsequent layers).

Some alternative embodiments may be created by selecting featuresassociated with one or more other embodiments or aspects and combiningthem with one or more features from one or more other embodiments oraspects.

Features of some embodiments include: (1) heat transfer arrays withmultilevel microchannels that are integrated with microjet arrays wherethe two elements are connected via two levels to maximize heat transfercapability and efficiency; (2) corrosion and erosion may be minimized byusing high strength electrodepositable materials (e.g. NiCo, palladium,rhodium, or the like in selected areas); (3) corrosion and erosion maybe minimized or at least effectively managed by local thickening atimpingement areas; (4) dimensions of features in a heat transfer arraymay be uniquely optimized for fluid flow, for example, slot jetdimensions and fin dimensions may vary from jet to jet and from inlet tooutlet to optimize or at least bring heat transfer to a desired level ofefficiency or effectiveness; (5) heat transfer arrays and cold platesmay be optimized to the unique requirements of specific heat sources bychanging dimensions and direction of fluid flow, locations of inlets andoutlets, and the like.

As noted previously, in some embodiments the bottom of each jet at oneor more locations, e.g. four locations, connect structurally to thesurface on to which jetting occurs. This means that not only do the jetsremove heat from the floor onto which jetting occurs via a flow ofjetted fluid but also via heat conduction upward from the floor throughthe metal of the jet. This means that the jet in addition to functioningas a jet also functions as a fin. Said another way, in theseembodiments, these fin structures are hollow and in addition toproviding fin functionality they also form jetting structures so as toprovided overall improved heat removal and more effective use ofvolumetric space. These jets/fins also provide further heat removal viaconducted heat by the lower portions of the jets/fins (the portionsbelow the top of the walls of the jetting wells) releasing conductedheat to the incoming jet stream via the interior surface of the jetstructure and to the exiting jet stream via the external surface of thejetting/fin structure. The upper surfaces of the jet releases furtherconducted heat via the flow of exhausted jetted fluid via the fluidflowing through the fluid exit path, channel, level or layer. Similarlythe fins located between the jets that define the jetting wells alsoconduct heat away from the heat source via contact with exiting jettedfluid along their side walls and along their upper surfaces as well asalong any supporting columns or jet side walls that extend upwardtherefrom. In some embodiments, like those shown, the fins (that alsofunction as jets) are elongated to help with fluid flow by reducing flowresistance while at the same time providing more surface area fortransferring heat from the sidewalls to the incoming and exiting fluid.

In some alternative embodiments more than one inlet may be used, morethan one outlet may be used, more than a single inlet level (e.g. in theZ-direction, i.e. direction parallel to an axis of layer stacking) andoutlet level may be used.

In some embodiments the trapped fluid flow through a whole thermalmanagement system may involve fluid transport from a primary heat pickup location, i.e. jetting impingement surface and primary heat transferregion, to an exit channel of a header or manifold, to a conventionalheat exchanger (e.g. that removes heat by transferring to another fluidsuch as air or to a larger sink), to an optional filter (e.g. with apore size of 1 Os of microns, to micron level. or finer), to a pump, toan optional filter (e.g. micron level filter or finer), to an inlet of aheader or manifold and back to the primary heat transfer location.

In some embodiments, a hybrid microjet and microchannel heat transferarray is provided to take advantage of the high convection performanceof the microjet and the high surface area of a microchannel. In someembodiments, the microjet may include fin functionality. In someembodiments cold plates are miniaturized by using a micro additivemanufacturing process (such as those described herein) alone or incombination with traditional manufacturing to produce micro heattransfer arrays in high volume. In some embodiments a multilayermicrochannel with microjets connecting the two layers creates 3-D flowbehavior that generates high convection coefficients and heat transferat all surfaces. In some embodiments, high strength materials like NiComay be used to minimize corrosion and the generation of particles thatcan jam the fluid system and cause failure of pumps or jets. In someembodiments, volumes with high fluid velocities or turbulent flow may bereinforced (with hard materials such as Rh) to minimize erosion of thesurface over time. In some embodiments, composite material constructionmay be used to allow for optimizing strength, conductivity, and surfaceproperties as needed.

Various embodiments of the invention may provide thermal management forvarious devices and the heat transfer arrays may be used to move heatgenerated by a variety of devices including for example: (1) an IC; (2)a microprocessor; (3) an SOC; (4) an RFIC, e.g. an RF transmitter or RFreceiver; (5) an optical transmitter or receiver; (6) a power amplifier;(7) a GPU; (8) a CPU; (9) a DSP; (10) an ASIC; (11) an APU; (12) an LED;(13) a laser diode; (14) a power electronic device, e.g. a powerinverter or a power converter; (15) a photonic devices, (16) apropulsion system; (17) a solar array, e.g. for a micro satellite; (18)a radiator, e.g. for a micro satellite; (19) an engine of a micro drone;(20) a spacecraft component such as an SSPA; (21) a traveling wave tubeamplifier; (22) a package that holds one or more of the devices of(1)-(21), and (23) a stack or plurality of stacks of devices sandwichedbetween separated arrays or interleaved with multiple arrays.

Further Comments and Conclusions

Structural or sacrificial dielectric materials may be incorporated intovarious embodiments of the present invention in a variety of differentways. Such materials may form a third or higher material on selectedlayers or may form one of the first two materials deposited on somelayers. Additional teachings concerning the formation of structures ondielectric substrates and/or the formation of structures thatincorporate dielectric materials into the formation process andpossibility into the final structures are set forth in a number ofpatent applications filed Dec. 31, 2003. The first of these filings isU.S. Patent Application No. 60/534,184 which is entitled“Electrochemical Fabrication Methods Incorporating Dielectric Materialsand/or Using Dielectric Substrates”. The second of these filings is U.S.Patent Application No. 60/533,932, which is entitled “ElectrochemicalFabrication Methods Using Dielectric Substrates”. The third of thesefilings is U.S. Patent Application No. 60/534,157, which is entitled“Electrochemical Fabrication Methods Incorporating DielectricMaterials”. The fourth of these filings is U.S. Patent Application No.60/533,891, which is entitled “Methods for Electrochemically FabricatingStructures Incorporating Dielectric Sheets and/or Seed layers That ArePartially Removed Via Planarization”. A fifth such filing is U.S. PatentApplication No. 60/533,895, which is entitled “ElectrochemicalFabrication Method for Producing Multi-layer Three-DimensionalStructures on a Porous Dielectric”. Additional patent filings thatprovide teachings concerning incorporation of dielectrics into the EFABprocess include U.S. patent application Ser. No. 11/139,262, filed May26, 2005, now U.S. Pat. No. 7,501,328, by Lockard, et al., and which isentitled “Methods for Electrochemically Fabricating Structures UsingAdhered Masks, Incorporating Dielectric Sheets, and/or Seed Layers thatare Partially Removed Via Planarization”; and U.S. patent applicationSer. No. 11/029,216, filed Jan. 3, 2005 by Cohen, et al., now abandoned,and which is entitled “Electrochemical Fabrication Methods IncorporatingDielectric Materials and/or Using Dielectric Substrates”. These patentfilings are each hereby incorporated herein by reference as if set forthin full herein.

Some embodiments may employ diffusion bonding or the like to enhanceadhesion between successive layers of material. Various teachingsconcerning the use of diffusion bonding in electrochemical fabricationprocesses are set forth in U.S. patent application Ser. No. 10/841,384which was filed May 7, 2004 by Cohen et al., now abandoned, which isentitled “Method of Electrochemically Fabricating Multilayer StructuresHaving Improved Interlayer Adhesion” and which is hereby incorporatedherein by reference as if set forth in full. This application is herebyincorporated herein by reference as if set forth in full.

Though the embodiments explicitly set forth herein have consideredmulti-material layers to be formed one after another. In someembodiments, it is possible to form structures on a layer-by-layer basisbut to deviate from a strict planar layer on planar layer build upprocess in favor of a process that interlaces material between thelayers. Such alternative build processes are disclosed in U.S.application Ser. No. 10/434,519, filed on May 7, 2003, now U.S. Pat. No.7,252,861, entitled Methods of and Apparatus for ElectrochemicallyFabricating Structures Via Interlaced Layers or Via Selective Etchingand Filling of Voids. The techniques disclosed in this referencedapplication may be combined with the techniques and alternatives setforth explicitly herein to derive additional alternative embodiments. Inparticular, the structural features are still defined on aplanar-layer-by-planar-layer basis but one or more materials associatedwith some layers are formed along with material for other layers suchthat interlacing of deposited material occurs. Such interlacing may leadto reduced structural distortion during formation or improved interlayeradhesion. This patent application is herein incorporated by reference asif set forth in full.

The patent applications and patents set forth below are herebyincorporated by reference herein as if set forth in full. The teachingsin these incorporated applications can be combined with the teachings ofthe instant application in many ways: For example, enhanced methods ofproducing structures may be derived from some combinations of teachings,enhanced structures may be obtainable, enhanced apparatus may bederived, and the like.

US Pat App No., Filing Date US App Pub No., Pub Date US Patent No., PubDate Inventor, Title 10/830,262 - Apr. 21, 2004 Cohen, “Methods ofReducing Interlayer Discontinuities in 2004-0251142A - Dec. 16, 2004Electrochemically Fabricated Three-Dimensional Structures” 7,198,704 -Apr. 3, 2007 10/697,597 - Dec. 20, 2002 Lockard, “EFAB Methods andApparatus Including Spray 2004-0146650A - Jul. 29, 2004 Metal or PowderCoating Processes” — 10/607,931 - Jun. 27, 2003 Brown, “Miniature RF andMicrowave Components and 2004-0140862 - Jul. 22, 2004 Methods forFabricating Such Components” 7,239,219 - Jul. 3, 2007 10/841,100 - May7, 2004 Cohen, “Electrochemical Fabrication Methods Including Use2005-0032362 - Feb. 10, 2005 of Surface Treatments to Reduce Overplatingand/or 7,109,118 - Sep. 19, 2006 Planarization During Formation ofMulti-layer Three- Dimensional Structures” 10/434,294 - May 7, 2003Zhang, “Electrochemical Fabrication Methods With Enhanced2004-0065550A - Apr. 8, 2004 Post Deposition Processing” — 10/434,103 -May 7, 2004 Cohen, “Electrochemically Fabricated Hermetically Sealed2004-0020782A - Feb. 5, 2004 Microstructures and Methods of andApparatus for Producing 7,160,429 - Jan. 9, 2007 Such Structures”10/841,006 - May 7, 2004 Thompson, “Electrochemically FabricatedStructures Having 2005-0067292 - May 31, 2005 Dielectric or Active Basesand Methods of and Apparatus for — Producing Such Structures”10/841,347 - May 7, 2004 Cohen, “Multi-step Release Method forElectrochemically 2005-0072681 - Apr. 7, 2005 Fabricated Structures” —60/533,947 - Dec. 31, 2003 Kumar, “Probe Arrays and Method for Making” —— 11/733,195 - Apr. 9, 2007 Kumar, “Methods of Forming Three-DimensionalStructures 2008-0050524 - Feb. 28, 2008 Having Reduced Stress and/orCurvature” — 11/506,586 - Aug. 8, 2006 Cohen, “Mesoscale and MicroscaleDevice Fabrication 2007-0039828 - Feb. 22, 2007 Methods Using SplitStructures and Alignment Elements” 7,611,616 - Nov. 3, 2009 10/949,744 -Sep. 24, 2004 Lockard, “Three-Dimensional Structures Having Feature2005-0126916 - Jun. 16, 2005 Sizes Smaller Than a Minimum Feature Sizeand Methods 7,498,714 - Mar. 3, 2009 for Fabricating” 13/273,873 - Oct.14, 2011 Chen, “Cantilever Microprobes For Contacting Electronic2012-0064227 - Mar. 15, 2012 Components and Methods for Making SuchProbes” 8,723,543 - May 13, 2014 12/631,632 - Dec. 4, 2009 Kim,“Microprobe Tips and Methods for Making” 2010-0155253 - Jun. 24, 2010 —12/345,624 - Dec. 29, 2008 Cohen, “Electrochemical Fabrication MethodIncluding Elastic — Joining of Structures” 8,070,931 - Dec. 6, 201110/995,609 - Nov. 22, 2004 Cohen, “Electrochemical Fabrication ProcessIncluding 2005-0202660 - Sep. 15, 2005 Process Monitoring, MakingCorrective Action Decisions, and — Taking Appropriate Actions”11/028,957 - Jan. 3, 2005 Cohen, “Electrochemical Fabrication MethodsIncorporating 2005-0202667 - Sep. 15, 2005 Dielectric Materials and/orUsing Dielectric Substrates” — 11/029,218 - Jan. 3, 2005 Cohen,“Electrochemical Fabrication Methods Incorporating 2005-0199583 - Sep.15, 2005 Dielectric Materials and/or Using Dielectric Substrates”7,524,427 - Apr. 28, 2009 12/906,970 - Oct. 18, 2010 Wu, “Multi-Layer,Multi-Material Fabrication Methods for 2011-0132767 - Jun. 11, 2009Producing Micro-Scale and Millimeter-Scale Devices with 8,613,846 - Dec.24, 2013 Enhanced Electrical or Mechanical Properties” 11/029,218 - Jan.3, 2005 Cohen, “Electrochemical Fabrication Methods Incorporating2005-0199583 - Sep. 15, 2005 Dielectric Materials and/or UsingDielectric Substrates” 7,524,427 - Apr. 28, 2009 12/345,624 - Dec. 29,2008 Cohen, “Electrochemical Fabrication Method Including Elastic —Joining of Structures” 8,070,931 - Dec. 6, 2011 11/029,221 - Jan. 3,2005 Cohen, “Electrochemical Fabrication Process for Forming2005-0215023 - Sep. 29, 2005 Multilayer Multimaterial MicroprobeStructures” 7,531,077 - 03-Jan-05 12/828,274 - Jun. 30, 2010 Smalley,“Enhanced Methods for at least Partial In Situ — Release of SacrificialMaterial From Cavities or Channels 8,262,916 - Sep. 11, 2012 and/orSealing of Etching Holes During Fabrication of Multi- Layer Microscaleor Millimeter-scale Complex Three- Dimensional Structures” 14/280,517 -May 16, 2014 Cohen, “Stacking and Bonding Methods for Forming Multi- —Layer, Three-Dimensional, Millimeter Scale and Microscale 9,919,472 -Mar. 20, 2018 Structures” 14/333,476 - Jul. 14, 2014 Jensen, “BatchMethods of Forming Microscale or Millimeter 2015-0021299 - Jan. 22, 2015Scale Structures Using Electro Discharge Machining Alone or — InCombination with Other Fabrication Methods” 14/660,903 - Mar. 17, 2015Chen, “Methods of Forming Parts from One or More Layers — of DepositedMaterial(s)” — 14/720,719 - May 22, 2015 Veeramani, “Methods of FormingParts Using Laser — Machining” 9,878,401 - Jan. 30, 2018

Though various portions of this specification have been provided withheaders, it is not intended that the headers be used to limit theapplication of teachings found in one portion of the specification fromapplying to other portions of the specification. For example, it shouldbe understood that alternatives acknowledged in association with oneembodiment or aspect, are intended to apply to all embodiments oraspects to the extent that the features of the different embodiments oraspects make such application functional and do not otherwise contradictor remove all benefits of the adopted embodiment or aspect. Variousother embodiments of the present invention exist. Some of theseembodiments may be based on a combination of the teachings herein setforth herein directly with various teachings incorporated herein byreference.

In view of the teachings herein, many further embodiments, alternativesin design and uses of the embodiments of the instant invention will beapparent to those of skill in the art. As such, it is not intended thatthe invention be limited to the particular illustrative embodiments,alternatives, and uses described above but instead that it be solelylimited by the claims presented hereafter.

We claim:
 1. A method of cooling a semiconductor device, comprising: (a)providing at least one heat transfer array, comprising a plurality ofstacked and adhered layers comprising at least one metal wherein each ofthe at least one heat transfer array comprises features selected fromthe group consisting of: (1) a microjet array, (2) a plurality ofmicrojet structures and microchannels that receive fluid after beingjetted from jetting structures, and (3) a plurality of fins and microjetstructures wherein the fins comprise at least a portion of the jettingstructures including jetting channels and jetting orifices. (b) placingthe heat transfer array in physical contact with or in proximity to thesemiconductor device to be cooled to form a primary heat transfer regionhaving at least one cooling fluid impingement surface; (c) pumping acooling fluid into at least one inlet of the heat transfer array suchthat the cooling fluid is jetted onto the impingement surface to extractheat therefrom, then passing the heated cooling fluid to at least oneoutlet of the heat transfer array, while continuing to extract heat fromthe heat transfer array, and then onto a heat exchanger where heat isremoved from the cooling fluid to produce cooled cooling fluid; and (d)circulating the cooled cooling fluid from the heat exchanger back intothe at least one inlet of the heat transfer array to repeat a flow cycleto draw heat from the at least one semiconductor device.
 2. The methodof claim 1 wherein the heat transfer array is configured to use a heattransfer fluid that is a liquid.
 3. The method of claim 2 wherein theliquid comprises water.
 4. The method of claim 2 wherein the liquid doesnot undergo a phase change during a process of cooling a semiconductor.5. A thermal management system for a semiconductor device comprising:(1) at least one micro cold plate, comprising: (a) at least one fluidinlet header or manifold; (b) at least one fluid outlet header ormanifold; (c) a hybrid microjet and microchannel heat transfer array,comprising: (I) a plurality of microjet structures for directing a heattransfer fluid from the at least one fluid inlet header or manifold ontoat least one surface of a primary heat exchange region selected from thegroup consisting of: a. a surface of a heat source or a plurality ofseparated surfaces of a heat source; b. at least one surface inproximity to one or more heat source surfaces wherein a separationdistance between the at least one surface onto which jetting occurs anda surface or a plurality of separate surfaces of a heat source isselected from the group consisting of: (i) <=200 um, (ii) <=100 um,(iii) <=50 um, (iv) <=20 um, and (v) <=10 um; c. at least one surface ofa solid material separated from a surface or a plurality of separatesurfaces of a heat source by a gap that is occupied by at least onehighly conductive transfer material that may be a different solid, asemi-liquid, or a liquid wherein a thickness of the gap is selected fromthe group consisting of: (i) <=200 um, (ii) <=100 um, (iii) <=50 um,(iv) <=20 um, and (v) <=10 um); and d. at least one surface of a solidthat is in intimate contact with a surface or a plurality of separatesurfaces of a heat source; and (II) a plurality of post jettingmicrochannel flow paths to direct the heat transfer fluid from theprimary heat exchange region to the at least one outlet header ormanifold, wherein the at least one surface of the primary heat exchangeregion onto which jetting occurs is closer, in the jetting direction, tothe surface or the plurality of separate surfaces of the heat sourcethan are the microchannel flow paths. (2) at least one flow path to moveheated fluid, directly or indirectly, from the fluid outlet header ormanifold of the at least one micro cold plate to a heat exchanger; (3)at least one flow path to move cooled fluid, directly or indirectly,from the heat exchanger back into the inlet header or manifold of the atleast one micro cold plate; and (4) at least one pump functionallyconfigured to direct the fluid through the at least one cold plate tothe heat exchanger and back to the at least one cold plate, wherein theheat transfer array is configured to withdraw heat from a semiconductordevice.
 6. The system of claim 5 wherein the at least one surface ontowhich jetting occurs comprises a plurality of jetting well surfaces witheach jetting well surface surrounded by walls that direct fluid awayfrom the jetting well surfaces into the microjet flow paths.
 7. Thesystem of claim 6 wherein each of the plurality of jetting surfaces isconfigured to directly receive jetted fluid from a single jet orifice.8. The system of claim 7 wherein the jets have elongated cross-sectionalconfigurations (i.e. in a plane perpendicular to a jetting direction)with a length to width aspect ratio selected from the group consistingof: (i) <=10 to 1, (ii) <=5 to 1, (iii) <=3 to 1, or (iv) <=2 to
 1. 9.The system of claim 7 wherein the microchannels direct fluid receivedfrom the jetting structures along paths that flow past outside walls ofthe microjet structures initially in a direction that is substantiallyanti-parallel to the direction of jetting and then in a direction thatis substantially perpendicular to the direction of jetting.
 10. Thesystem of claim 7 wherein the at least one fluid inlet header ormanifold is spaced further from the surface onto which jetting occursthan does a flow path through the microchannels after the fluid leavesthe jetting wells.
 11. The system of claim 5 wherein the devicecomprises a component selected from the group consisting of: (1) an IC;(2) a microprocessor; (3) an SOC; (4) an RFIC, e.g. an RF transmitter orRF receiver; (5) an optical transmitter or receiver; (6) a poweramplifier; (7) a GPU; (8) a CPU; (9) a DSP; (10) an ASIC; (11) an APU;(12) an LED; (13) a laser diode; (14) a power electronic device, e.g. apower inverter or a power converter; (15) a photonic device, (16) apropulsion system; (17) a solar array, e.g. for a micro satellite; (18)a radiator, e.g. for a micro satellite; (19) an engine of a micro drone;(20) a spacecraft component such as an SSPA; (21) a traveling wave tubeamplifier; (22) a package that holds one or more of the devices of(1)-(21), and (23) a stack or plurality of stacks of devices sandwichedbetween separated heat transfer arrays or interleaved with multiple heattransfer arrays.
 12. The system of claim 5 wherein the majority of theheat exchange from a solid to the fluid occurs via a surface of a firstmetal and wherein selected portions of the heat transfer array areformed from a second metal of higher thermal conductive than the firstmetal such that heat conductivity as a whole is improved relative to theheat conductivity if the second metal were replaced with the firstmetal.
 13. The system of claim 5 wherein regions onto which jetted fluidimpinges are strengthened with a material different from that used toform the side walls of the jetting structures.
 14. The system of claim 5wherein the heat transfer array comprises a plurality of adhered planarlayers of at least one material where successive layers can bedistinguished by stair-stepped configurations and wherein layers extendlaterally in a cross-sectional dimension and a layer stacking axis issubstantially perpendicular to a direction of fluid jetting.
 15. Thesystem of claim 5 wherein the heat to be removed requires a heat flux,from at least a portion of the primary heat transfer region, selectedfrom the group consisting of (i) >=200 W/cm², (ii) >=400 W/cm² and(iii) >=800 W/cm²).
 16. The system of claim 15 wherein the temperatureof the surface or the plurality of separate surfaces of the heat sourceare to be held to a temperature selected from the group consisting of(i) <=100° C., (ii) <=80° C., and (iii <=65° C.
 17. The system of claim15 wherein a variation in temperature over the surface or the pluralityof separate surfaces of the heat source is to be held at a temperatureselected from the group consisting of (i) <=20° C., (ii) <=15° C., and(iii) <=10° C.
 18. The system of claim 17 wherein a flow of the heattransfer fluid through the heat transfer array is selected from thegroup consisting of (i) <=2.0 L/min per 4 mm×4 mm area covered by theheat transfer array, (ii) <=1 L/min per 4 mm×4 mm area covered by theheat transfer array, and (iii) <=0.5 L/min per 4 mm×4 mm area covered bythe heat transfer array.
 19. The system of claim 5 wherein at least aportion of the plurality of microjet structures provide flow paths witha cross-sectional dimension in the range selected from the groupconsisting of (1) 15 to 300 um and (2) 30-200 um.
 20. The system ofclaim 5 wherein at least a portion of the post jetting microchannelshave a cross-sectional dimension in the range selected from the groupconsisting of (1) 15-300 um and (2) 30-150 um.
 21. The system of claim 5wherein distal ends of a plurality of microjet structures are spacedfrom the at least one surface of the primary heat exchange region bylength in the range selected from the group consisting of (1) 15-200 umand (2) 30-100 um.
 22. The system of claim 5 wherein a first height ofat least a plurality of post jetting microchannels is in the rangeselected from the group consisting of (1) 40 to 600 um and (2) 80-300um, wherein the first height is measured along a portion of themicrochannels that directs fluid flow in a direction substantiallyanti-parallel to a direction of flow of fluid through the jettingstructures.
 23. The system of claim 5 wherein a height of at least aplurality of the jetting structures is in the range selected from thegroup consisting of (1) 300 um to 1 mm and (2) 400-800 um.
 24. Thesystem of claim 5 wherein a height of at least a plurality of themicrojet structures is selected from the group consisting of (1) 300 umto 2 mm and (2) 400-800 um, wherein a second height of at least aplurality of post jetting microchannels is selected from the groupconsisting of (1) 300-2000 um and (2) 600-2000 um, wherein the secondheight is measured along a portion of the microchannels that directsfluid flow in a direction substantially perpendicular to the directionof fluid flow through the microjet structures.
 25. The system of claim 5wherein a jetting well height extends from the at least one surface ofthe primary heat exchange region to a height that is above a height atwhich fluid exits the jetting structures.
 26. The system of claim 5wherein the heat transfer array is configured to use a heat transferfluid selected from the group consisting of: (1) a liquid, (2) water,and (3) a liquid that does not undergo a phase change during a processof cooling a semiconductor.
 27. The system of claim 5 wherein a solidmaterial separating two adjacent jetting wells comprises a core materialsurrounded at least partially by a shell material wherein the corematerial has a higher thermal conductivity than does the shell materialand also has a lower yield strength.
 28. The system of claim 5 whereinthe plurality of jetting structures function as fins that contact the atleast one surface of the at least one primary heat exchange regionwhereby a lowest portion of the plurality of jetting structures is insolid-to-solid contact with the at least one surface of the primary heatexchange region while at least one opening exists in the jettingstructures above the at least one surface of the primary heat exchangeregion such that the jetted fluid is free from an enclosing jettingchannel within the jetting structure to impinge on the at least onesurface of the primary heat exchange region.
 29. The system of claim 28wherein a filter is located in a position selected from the groupconsisting of: (1) along a flow path between the outlet and a pump, (2)along a flow path between the pump and the inlet, and (3) along a flowpath between the pump and the heat exchanger.
 30. The system of claim 28wherein the pump has a position selected from the group consisting of:(1) mounted to a header or manifold of the cold plate and (2) spacedfrom the cold plate.
 31. The system of claim 28 additionally comprisingat least one temperature sensor and a control system having afunctionality selected from the group consisting of: (1) turning on thepump when a detected temperature is greater than a high temperature setpoint and (2) turning off the pump when a detected temperature is lessthan a low temperature set point.
 32. The system of claim 28 wherein thesystem comprises at least two microjet arrays with a relationshipselected from the group consisting of: (1) spaced from one another toremove heat from separated portions of a single integrated circuit and(2) spaced from one another to remove heat from two different integratedcircuits.
 33. The system of claim 28 additionally comprising a pressuresensor to monitor fluid pressure in at least one flow path.
 34. Thesystem of claim 28 wherein the micro cold plate comprises a singlestructure that provides both the inlet header or manifold and the outletheader or manifold.
 35. The system of claim 28 wherein the surface ontowhich jetting occurs is closer, in the jetting direction, to the heatsource than are the plurality of post jetting microchannel flow paths.36. The system of claim 28 wherein each fin provides a plurality ofcontacts to the surface onto the at least one surface of the primaryheat exchange region onto which jetting occurs.
 37. The system of claim28 wherein each fin has an elongated cross-sectional configuration.